• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3336-3346
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• 2022

In general, a number of severe accident scenarios derived from Level 2 probabilistic safety assessment (PSA) are typically grouped into several categories to efficiently evaluate their potential impacts on the public with the assumption that scenarios within the same group have similar source term characteristics. To date, however, grouping by similar source terms has been completely reliant on qualitative methods such as logical trees or expert judgements. Recently, an exhaustive simulation approach has been developed to provide quantitative information on the source terms of a large number of severe accident scenarios. With this motivation, this paper proposes a machine learning-based categorization method based on exhaustive simulation for grouping scenarios with similar accident consequences. The proposed method employs clustering with an autoencoder for grouping unlabeled scenarios after dimensionality reductions and feature extractions from the source term data. To validate the suggested method, source term data for 658 severe accident scenarios were used. Results confirmed that the proposed method successfully characterized the severe accident scenarios with similar behavior more precisely than the conventional grouping method.

• Journal of Korean Physical Therapy Science
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• v.7 no.1
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• pp.333-352
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• 2000

The objective of this study was to identify the effects of the cognitive performance of stroke patients on their motor function recovery after comprehensive rehabilitation management. The subjects of this study were 41 stroke in-patients of the Rehabilitation Hospital, College of Medicine, Yonsei University, hospitalized during the period from September 1, 1997 to May 5, 1998. The cognitive performance was measured using a Mini-Mental State Examination(MMSE) and the motor function recovery using Motor Assessment Scale(MAS). The data were analyzed by the paired t-test, independent t-test, a one way ANOVA, and Pearson's correlation coefficiency. The findings were as follows: 1. There was a significant difference found in the motor function recovery level after the comprehensive rehabilitation management. 2. There was no significant difference found in relation to sex, age, cause of stroke, laterality of paralysis and the level of spasticity. However, there was a big difference between pre- and post-treatment regarding the treatment period. 3. In line with the cognitive performance level, there was a significant difference found in the motor function recovery level after the comprehensive rehabilitation management. 4. The correlation between the elements of the cognitive performance and the motor recovery was found to be high in orientation, attention, calculation, and language. Those elements were expected to give larger effects on motor recovery after the comprehensive rehabilitation management. Based on this study, the cognitive performance level was found to play an important role in bringing effects on motor recovery after the comprehensive rehabilitation management of stroke patients. And the evaluation on the motor recovery based on quality would be also expected to be examined, as well as the cognitive performance level test accompanied by Intelligence Quality(IQ) test.

• Journal of Korea Technology Innovation Society
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• v.15 no.2
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• pp.461-479
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• 2012

In this study, new evaluation perspective and analysis methodology are suggested to assess the technological level of new product produced by national large R&D program and applied to case analysis of the superconducting cable technology. Logical Procedures for the assessment of the technological level include essential technology classification, analysis of evaluation factors, structure and content of assessment items, presentation method of the analysis result. Variable with technological properties are employed to analyze the relative competitiveness subjectively. The principal component analysis are applied to measure the relative competitiveness in terms of size and position. Finally the combined results of technology and right evaluation show that the technology level of DAPAS superconducting cables lies somewhere between 96.11% and 101.76% compared with a global leader in technology. The result provides sufficient evidences that it secures technological edges over other competitors. Therefore it can be called as a globally leading technology. New evaluation perspective and analysis methodology suggested can be applied usefully to assess the technology level of public large-scale R&D program.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2221-2229
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• 2020

After the Fukushima Daiichi nuclear power plant (NPP) accident, level 3 probabilistic safety assessment (PSA) has emerged as an important task in order to assess the risk level of the multi-unit NPPs in a single nuclear site. Accurate calculation of the radionuclide concentrations and exposure doses to the public is required if a nuclear site has multi-unit NPPs and large number of people live near NPPs. So, there has been a great need to develop a new method or procedure for the fast and accurate offsite consequence calculation for the multi-unit NPP accident analysis. Since the multi-unit level 3 PSA is being currently performed assuming that all the NPPs are located at the same position such as a center of mass (COM) or base NPP position, radionuclide concentrations or exposure doses near NPPs can be drastically distorted depending on the locations, multi-unit NPP alignment, and the wind direction. In order to overcome this disadvantage of the COM method, the idea of a new multiple location (ML) method was proposed and implemented into a new tool MURCC (multi-unit radiological consequence calculator). Furthermore, the MURCC code was further improved for the multi-unit level 3 PSA that has the arbitrary number of multi-unit NPPs. The objectives of this study are to (1) qualitatively and quantitatively compare COM and ML methods, and (2) demonstrate the strength and efficiency of the ML method. The strength of the ML method was demonstrated by the applications to the multi-unit long-term station blackout (LTSBO) accidents at the four-unit Vogtle NPPs. Thus, it is strongly recommended that this ML method be employed for the offsite consequence analysis of the multi-unit NPP accidents.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1261-1266
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• 2021

Existing information security risk assessment methods focus on evaluating the vulnerability of information assets. However, when the form of information assets changes and new types of information assets emerge, there is a limitation in that the evaluation standards for them are also added or deleted. Existing methods have insufficient research on the path through which cyber threats are introduced. In particular, there is very little research on blocking the inflow path for web-based information systems with public IPs. Therefore, this paper introduces the main research contents of the BDLA (Blockade and Defense Level Analysis)-based information security risk assessment model. In addition, by applying the BDLA-based information security risk assessment model, the information security risk level was studied by measuring the blockade level and security equipment level of 17 public institutions.

• Korean Medical Education Review
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• v.20 no.3
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• pp.164-172
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• 2018

The aim of this study is to determine whether the 65 competencies, defined in "the role of Korean doctor, 2014", are suitable for basic medical education phase in Korea. It seeks to analyze the gap among the educational reality and expectation, assessment situation of the competencies above. We also try to define issues of the development, application and assessment phases of competency-based medical education (CBME) at individual medical schools. We designed survey tools based on the Miller's assessment pyramid (knowledge, explanation, demonstration, and performance) for each of the 65 competencies. The survey distributed to 41 medical schools in April 2015 and 38 replies were received (92.7%). Competencies that matched both the educational reality and expectation were numbers 1 (patient care), 33 (social accountability), and 49 (professionalism). However, all the other competencies ranked lower in current status than that of desirable level. 54 out of 65 competencies (83.07%) remained at the knowledge and explanation level when each competence were assessed. In the development, application, and assessment phases of CBME, common issues that medical schools commonly noted were difficulty linking competencies to curriculum preparation and student assessment, the lack of faculty's understanding, difficulty to reach consensus among faculties, and absence of teaching and learning methods and assessment tools that fits CBME. For the successful settle down of CBME, there is a need for efforts to develop the model of graduate outcomes, to share information and experience, and to operate faculty development program by the medical education communities.

• Communications of Mathematical Education
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• v.29 no.4
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• pp.625-642
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• 2015

The purpose of this study was to develop and verify the feedback-enhanced performance assessment model through a variety of assessment strategies focused on the development of students. In order to achieve the purpose of this study, we analyzed the achievements of the sixth grade curriculum standards and set the central achievement standards in core competencies. We then established an evaluation plan to take advantage of a variety of methods and develop an assessment tool for process-based evaluation during lessons. We applied this assessment model to 6th grade students while teaching and learning mathematics in the classroom. The result of applying the performance evaluation model showed the improvement of students' reflective thinking ability. Also, some students who was not achieved at the level of 'N' could develop to the level of 'N + 1'. A long term research using various assessment strategies should be continued for effective help of students' mathematical development.

• Journal of Environmental Health Sciences
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• v.45 no.1
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• pp.9-17
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• 2019

Objectives: This study examined the safety of tattoo ink by analyzing the phenol contents in tattoo inks and its risk assessment of selected phenol. Methods: A sample of 30 tattoo inks was purchased, the phenol contents were analyzed, and a risk assessment on dermal exposure from tattooing was carried out. Hazard identification was collected from toxicity data on systemic effects caused by dermal exposure to phenol, and the most sensitive toxicity value was adopted. Exposure assessment ($Exposure_{phenol}$) was calculated by applying phenol contents and standard exposure factors, while dose-response assessment was based on the collected toxicity data and skin absorption rate of phenol, assessment factors (AFs) for derived no-effect level ($DNEL_{demal}$). In addition, the risk characterization was calculated by comparing the risk characterization ratio (RCR) with $Exposure_{phenol}$ and $DNEL_{dermal}$ Results: The phenol concentration in the 30 products was from 1.4 to $649.1{\mu}g/g$. The toxicity value for systemic effects of phenol was adopted at 107 mg/kg. $Exposure_{phenol}$ in tattooing was from 0.000087 to 0.040442 mg/kg. $DNEL_{dermal}$ was calculated at 0.0072 mg/kg (=toxicity value 107 mg/kg ${\div}$ AFs 650 ${\times}$ skin absorption rate 4.4%). Thirteen out of 30 products showed an RCR between 1.02 and 5.62. The RCR of all red inks was above 1. Conclusions: Phenol was detected in all of the 30 tattoo inks, and the RCR of 13 products above 1 indicates a high level of risk concern, making it necessary to prepare safety management standards for phenol in tattoo inks.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.350-358
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• 2022

Objectives: For chemical risk assessment in workplaces, it is necessary to determine a reference value through hazard assessment. In general, OEL (Occupational Exposure Limit) is used for this value. However, since chemicals with OEL were not enough, the concept of DNEL (Derived No Effect Level) was introduced in chemical safety assessment. In this study, the possibility and approach of applying DNEL for chemical risk assessment in domestic workplaces were investigated. Methods: The characteristics of OEL and DNEL were investigated. In addition, ACGIH TLV and GESTIS DNEL were compared and the corresponding scopes were analyzed among the chemical substances notified in South Korea. Results: OEL and DNEL are similar concepts reflecting reference values that should not be exposed based on health effects. While their evaluation and derivation are determined based on similar information and procedures, they may vary depending on the responsible actor, data availability, principles of judgment, and more. As a result of the comparative analysis of ACGIH TLV and GESTIS DNEL, it was confirmed that there is some correlation between TWA and DNEL. The conservatism of DNEL was around 50%. Additionally, it was found that the available range of DNEL among chemicals in South Korea is considerable. Conclusions: This study showed that DNEL can be applied when assessing the risk of chemical substances in domestic workplaces considering several regards. However, since this is not the same level as OEL, we have proposed a proper approach to carry out risk assessment step by step.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.455-455
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• 2021

The Life Cycle Assessment (LCA) as an environmental impact assessment tool has received increasing attention over the years. Unlike the water footprint (WF) and carbon footprint (CF) assessments whose focus is only on a single environmental aspect, the LCA systematically analyzes the different impacts along the entire life cycle, making possible the identification of potential environmental tradeoffs. In Korea, LCA has drawn much attention from both industry and academia since the mid-90s. However, the level of Korea-related LCA studies with respect to different sectors in the past 20 years has not been analyzed. This study, therefore, sought to assess the status of environmental Life Cycle Assessment (LCA) studies in Korea, with a view to understanding the current level of sustainability reporting and identify potential research gaps. Online searches of English written articles published between 2000 and 2019 were conducted on Google, Google scholar, Scopus, and Web of Science databases using the Keywords "life cycle assessment", "lca", and "Korea." At the end of the search, about 88 LCA related studies were identified for Korea within the study period. Majority of these studies focused on the construction (49%) and energy (31%) sectors with fewer environmental studies on the transportation (9%), manufacturing (8%), agriculture (2%), and information and communication (1%) industries. Based on publication trend, results show that LCA studies in Korea have been on the rise in the past 20 years, even though the number of publications has not followed a constant pace. In comparison with the economic sectors of the country, reports show an inadequacy in the coverage of major industries of growing economic relevance like the tourism, health, and agriculture, suggesting a need to further increase and improve LCA related studies in these sectors.