• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.213-224
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• 2023

Type II solar radio bursts show frequency drifts from high to low over time. They have been known as a signature of coronal shock associated with Coronal Mass Ejections (CMEs) and/or flares, which cause an abrupt change in the space environment near the Earth (space weather). Therefore, early detection of type II bursts is important for forecasting of space weather. In this study, we develop a deep-learning (DL) model for the automatic detection of type II bursts. For this purpose, we adopted a 1-D Convolution Neutral Network (CNN) as it is well-suited for processing spatiotemporal information within the applied data set. We utilized a total of 286 radio burst spectrum images obtained by Hiraiso Radio Spectrograph (HiRAS) from 1991 and 2012, along with 231 spectrum images without the bursts from 2009 to 2015, to recognizes type II bursts. The burst types were labeled manually according to their spectra features in an answer table. Subsequently, we applied the 1-D CNN technique to the spectrum images using two filter windows with different size along time axis. To develop the DL model, we randomly selected 412 spectrum images (80%) for training and validation. The train history shows that both train and validation losses drop rapidly, while train and validation accuracies increased within approximately 100 epoches. For evaluation of the model's performance, we used 105 test images (20%) and employed a contingence table. It is found that false alarm ratio (FAR) and critical success index (CSI) were 0.14 and 0.83, respectively. Furthermore, we confirmed above result by adopting five-fold cross-validation method, in which we re-sampled five groups randomly. The estimated mean FAR and CSI of the five groups were 0.05 and 0.87, respectively. For experimental purposes, we applied our proposed model to 85 HiRAS type II radio bursts listed in the NGDC catalogue from 2009 to 2016 and 184 quiet (no bursts) spectrum images before and after the type II bursts. As a result, our model successfully detected 79 events (93%) of type II events. This results demonstrates, for the first time, that the 1-D CNN algorithm is useful for detecting type II bursts.

• Composites Research
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• v.36 no.6
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• pp.435-440
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• 2023

This study aimed to enhance the thermal conductivity of B₄C/Al composite materials, commonly used in transport/storage containers for spent nuclear fuel, by incorporating both boron carbide (B₄C) and cubic boron nitride(cBN) as reinforcing agents in an aluminum (Al) matrix. The composite materials were successfully manufactured through a stir casting process and practical neutron-absorbing materials were obtained by rolling the fabricated composite ingot. The evaluation of the thermal conductivity of the fabricated composites was carried out because thermal conductivity is critical for neutron absorbing materials. The thermal conductivity measurement results indicated an approximately 3% increase in thermal conductivity under the same volume fraction when compared to composite materials using only B₄C particles. Through neutron absorption cross-sectional area calculations, it was confirmed that the neutron absorption capability decreased to a negligible level. Based on the findings of this study, new design approaches for neutron absorption materials are proposed, contributing to the development of high-performance transport/storage containers.

• Journal of Industrial Convergence
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• v.22 no.2
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• pp.143-151
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• 2024

This study compared the health behaviors, health related clinical characteristics between individuals with Glycated Hemoglobin A1C≧6.5% and < 6.5% in 30~59yr. Factors that were associated with A1C were identified by sex, health behaviors, health literacy. This study was an observational study with a cross-sectional design based on data from 2019~2021 Korea National Health and Nutrition Examination Survey. Multiple logistic regression analysis was employed to compute the odds ratios of health behaviors to identify the risk factors for Glycated Hemoglobin. The prevalence of A1C≧6.5% among the total was 79.4%(weighted %, n=348). In the A1C≧6.5%, 71.8% were men. In univariate logistic regression for A1C≧6.5%, sex, duration with diabetes, and body mass index(BMI) were influencing factors. In multiple logistic regression by sex, the factors associated with A1C≧6.5 in women were as follows: education(OR 4.5; 95% CI:1.1, 18.5), duration with diabetes(OR 2.9; 95% CI 1.1, 7.9). Strategies should be targeted to improve health behaviors and clinical characteristics for those in their sex, women in low education level, duration with diabetes. Moreover, healthcare providers should understand the barriers to health behaviors and health literacy to effectively deliver healthcare service.

• Journal of The Korean Association For Science Education
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• v.26 no.6
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• pp.753-764
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• 2006

The concept of blood circulation is so complex, dynamic and abstract that students have difficulty in understanding it and students' preconceptions hardly change into scientific concepts even after the lessons. The purpose of this study is to examine middle school, high school, and undergraduate students' understanding of blood circulation and to find the reason why the lack of deep understanding is displayed in students' explanations for the blood circulation. The study consists of three parts. First, the test was designed to investigate students' ideas for blood circulation as components of the structure, the function, the behavior and the mechanism. Second, the test was applied to 7th, 10th and 13th graders to investigate the students' understanding of blood circulation and categorize the types of students' blood circulation model according to their academic level. Finally, the concepts the students had little understanding of were analyzed to decide which ontological category they fell into and further to inquire the characteristics of each concept. The results showed that many students comprehend the structure and the function of blood circulation components well, and there was no significant difference in students' understanding according to the academic level. In contrast, understanding the behavior and the mechanism of circulatory components has remarkably improved in high school students and undergraduates majoring in science and engineering. Also, students' blood circulation models were classified into seven different types. High school students and undergraduates majoring in science and engineering demonstrated a significantly higher percentage on the type of double-loop-branch compared to other academic levels. In addition, it was found that the lack of deep understanding was caused by students' misconceiving the 'equilibrium' category as 'event' category.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.31.1-31.10
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• 2023

Background: With modernization, air pollution has become increasingly serious, and its effects on health have been revealed. As a result, public interest in environmental pollution has become critical for regulating air pollution. In our study, we aim to evaluate the impact of air pollution levels on public attention to environmental issues and examine whether awareness of the residential environment's impact on health acts as a mediator in this relationship. Methods: We conducted an analysis on 400 individuals surveyed in the preliminary feasibility study on adverse health effects in the Pohang Industrial Complex, to examine the relationship between particulate matter 2.5 (PM2.5) and attention to environmental issues. Logistic regression analysis was performed, and mediation analysis was used to determine whether awareness of the residential environment's impact on health mediated the relationship. Results: The logistic regression analysis results showed that PM2.5 levels were associated with attention to environmental issues (adjusted odds ratio [AOR]: 2.1; 95% confidence interval [CI]: 1.3-3.5; p = 0.003) and awareness of health impacts (AOR: 3.4; 95% CI: 1.6-7.1; p = 0.001). The PM2.5 levels showed 9.9% (95% CI: 5.4-14.0) increase in the prevalence of high attention to environmental issues, of which, only 1.0% (95% CI: 0.2-2.3) were mediated by health impact awareness. In the overall analysis, 10% of the total effect of PM2.5 on attention to environmental issues was mediated by health impact awareness. Conclusions: According to this study's results, there was a correlation between air pollution levels and attention to environmental issues. Awareness of the health impacts of air pollution partially mediated the effect of air pollution levels on attention to environmental issues. In future studies, it is recommended to identify other mediators to further understand this structure.

• Korean Journal of Radiology
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• v.20 no.8
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• pp.1275-1284
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• 2019

Objective: To develop algorithms using convolutional neural networks (CNNs) for automatic segmentation of acute ischemic lesions on diffusion-weighted imaging (DWI) and compare them with conventional algorithms, including a thresholding-based segmentation. Materials and Methods: Between September 2005 and August 2015, 429 patients presenting with acute cerebral ischemia (training:validation:test set = 246:89:94) were retrospectively enrolled in this study, which was performed under Institutional Review Board approval. Ground truth segmentations for acute ischemic lesions on DWI were manually drawn under the consensus of two expert radiologists. CNN algorithms were developed using two-dimensional U-Net with squeeze-and-excitation blocks (U-Net) and a DenseNet with squeeze-and-excitation blocks (DenseNet) with squeeze-and-excitation operations for automatic segmentation of acute ischemic lesions on DWI. The CNN algorithms were compared with conventional algorithms based on DWI and the apparent diffusion coefficient (ADC) signal intensity. The performances of the algorithms were assessed using the Dice index with 5-fold cross-validation. The Dice indices were analyzed according to infarct volumes (< 10 mL, ≥ 10 mL), number of infarcts (≤ 5, 6-10, ≥ 11), and b-value of 1000 (b1000) signal intensities (< 50, 50-100, > 100), time intervals to DWI, and DWI protocols. Results: The CNN algorithms were significantly superior to conventional algorithms (p < 0.001). Dice indices for the CNN algorithms were 0.85 for U-Net and DenseNet and 0.86 for an ensemble of U-Net and DenseNet, while the indices were 0.58 for ADC-b1000 and b1000-ADC and 0.52 for the commercial ADC algorithm. The Dice indices for small and large lesions, respectively, were 0.81 and 0.88 with U-Net, 0.80 and 0.88 with DenseNet, and 0.82 and 0.89 with the ensemble of U-Net and DenseNet. The CNN algorithms showed significant differences in Dice indices according to infarct volumes (p < 0.001). Conclusion: The CNN algorithm for automatic segmentation of acute ischemic lesions on DWI achieved Dice indices greater than or equal to 0.85 and showed superior performance to conventional algorithms.

• The Journal of Korean Society for School & Community Health Education
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• v.25 no.2
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• pp.71-81
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• 2024

Purpose: This study aims to identify research trends in papers related to the elderly and the disabled published in the journal of Korean society for school & community health education from 2000 to 2023 and seek the direction of the academic development of this journal in the future. Method: A total of 26 articles related to the elderly and the disabled, who are vulnerable groups, were analyzed by year by analyzing the specific subjects, research themes, research design, data collection methods, and keywords of papers published from 2000 to 2023. Results: Looking at the research subjects, studies on the elderly (18 studies) accounted for a larger proportion than studies on the disabled (8 studies). Research themes in the field of healthy living practices for the elderly (44.4%) and research in the field of mental health management (37.5%) for the disabled accounted for a high proportion. The design of research were mostly quantitative and cross-sectional studies. Data collection is mostly based on secondary data. In studies targeting the elderly, keywords appeared in the following order: 'Health' and 'Elderly'. And research targeting the disabled appeared in the following order: 'Disabilities', 'Health', and 'COVID-19'. Additionally, research on the elderly and the disabled has recently shown an increasing trend. Conclusion: Research on the elderly and the disabled has been conducted in line with the purpose of the Korean society for school & community health education, However, In terms of quantitative expansion and qualitative research, research themes, research designs, and data collection methods must be diversified. Methods, public perception. Additionally, research on vulnerable groups that fit the public health promotion and health education paradigm is needed.

• Journal of dental hygiene science
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• v.18 no.2
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• pp.85-96
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• 2018

The purpose of this study is to propose learning objectives in social dental hygiene by analyzing and reviewing learning objectives in oral health administration area of the existing public oral health. This study is a cross-sectional study. The subjects of the study selected with convenience extraction were 15 members of the social dental hygiene subcommittee of the Korean Society of Dental Hygiene Science. Data collection was conducted by self-filling questionnaire. The research tool is from 48 items of A division in the book of learning objectives in the dental hygienist national examination, and this study classified each of them into 'dental hygiene job relevance', 'dental hygiene competency relevance', 'timeliness', and 'value discrimination of educational goal setting' to comprise 192 items. Also, to collect expert opinions, this study conducted Delphi survey on 7 academic experts. Statistical analysis was performed using the IBM SPSS Statistics ver. 23.0 program (IBM Co., Armonk, NY, USA). Recoding was performed according to the degree of relevance of each learning objective and frequency analysis was performed. This study removed 18 items from the whole learning objectives in the dental hygienist national examination in the oral health administration area of public oral health. Fifteen revisions were made and 15 existing learning objectives were maintained. Forty-five learning objectives were proposed as new social dental hygiene learning objectives. The topics of learning objectives are divided into social security and medical assistance, oral health care system, oral health administration, and oral health policy. As a result of this study, it was necessary to construct the learning objectives of social dental hygiene in response to changing situation at the time. The contents of education should be revised in order of revision of learning objectives, development of competency, development of learning materials, and national examination.

• Journal of Korean Home Economics Education Association
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• v.18 no.1 s.39
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• pp.17-29
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• 2006

The purpose of this research was to examine the problems, confidence and satisfaction of teachers on the subject ${\ulcorner}technology and home economics{\lrcorner}$ in the 7th national curriculm. For this research, questionnaires were sent by post to teachers who teach technology and home economics in middle schools and high schools. The collected questionnaires were technically analyzed by SPSS/WIN 10.0 program, which measured frequency, percentage, average, standard deviation. According to the types of data, they were also analyzed by t-test and cross tabulation analyses. The results of this research were summarized as follows. 1) There were two teaching types of technology and home economics: the partial charge and the whole charge teaching according to teachers' majors, and both types occurred in similar percentage. The partial charge teaching means that teachers majoring in technology teach only the technology part and teachers majoring in home economics teach only the home economics part when they teach the same subject, technology and home economics. These days the partial charge teaching more often occurs in national or public schools than in private schools, and in coeducational schools than in girls' or boys' schools. 2) The major problems of teaching technology and home economics were caused in order by teachers' lack of skills and knowledge which we not their own major, the lack of students' interests and teaching materials, and burden of tests. 3) Teachers' confidence in teaching the contents of the subject, technology and home economics, made a significant difference according to their majors. Teachers whose major was technology felt more confident when they taught the chapters of the textbooks related to their major, technology, while teachers whose major was home economics felt more confident when they taught the chapters of the textbooks related to their major, home economics. According to implementation types, the partial charge teaching gave higher confidence to the teachers than the whole charge one in teaching almost all the chapters of the textbook. 4) According to implementation types, teachers' satisfaction was showed to be higher in the partial charge teaching than in the whole charge one.

• Journal of agricultural medicine and community health
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• v.39 no.3
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• pp.161-175
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• 2014

Objectives: This study investigates the prevalence of suicide ideation and its the related factors by gender among Korean adults. Methods: National cross-sectional data from the database of the first and second year of $5^{th}$ Korean National Health and Nutritional Examination Survey (KNHANES V-1, V-2) were used for this study. 13,165 adults (${\geq}20$ years) were included in this analysis. Results: The prevalence of suicide ideation was 9.8% for men, 18.9% for women. Renal failure, depression, melancholy, stress, perceived health status, and smoking were significant risk factors among both men and women for suicide ideation. Divorced, separated or widowed of marital status and severe physical activity were related factors of suicide ideation for men. Low educational attainment, and alcohol dependency were associated factors of suicide ideation for women. Conclusions: There was gender difference of prevalence and risk factors of suicide ideation. These gender differences should be considered for planning and implementing suicide prevention program.