• Journal of the Korean Society of School Health
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• v.29 no.2
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• pp.90-97
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• 2016

Purpose: The purpose of this study was to investigate the relationship between sleep timing and depressive mood in Korean adolescents. Methods: The study analyzed the data from the 2007~2015 Korea Youth Risk Behavior Web-based Survey. A total of 541,693 students in grades 7~12 were included in the final analysis. Multivariable logistic regression was used to examine their sleep timing and depressive mood, adjusted for sex, grade, region, socioeconomic status, academic performance, alcohol, smoking and physical activity. Sleep duration and sleep quality were also included in our model to identify whether or not the effect of sleep timing on depression is mediated by sleep duration or sleep quality. Results: The prevalence of depressive mood was 32.7% and the mean sleep timing was 12:13 AM. After adjustment for eligible covariates, the association between sleep timing and depressive mood showed a J-shaped curve. Adolescents who slept at 8 pm~10 pm were 39% more likely to be depressive (OR = 1.39, 95% CI 1.30~1.40) and at 3 am~ 4 am were 67% more likely to be depressive (OR=1.67, 95% CI 1.64~1.70) than adolescents who slept at 11 pm~12 am. These associations persisted after being adjusted for sleep duration and sleep quality. Conclusion: Sleep timing was related to depression in adolescents, independent of sleep duration and sleep quality. It appears that there is a certain sleep timing beneficial to mental health of adolescents.

• Journal of Nutrition and Health
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• v.24 no.1
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• pp.48-57
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• 1991

The longitudinal changes on human milk volume per day and lactational performance of Korean primiparae(n=9) and multiparae(n=6) from 0.5 month to 5 months after parturition have been studied by test-weighing method. The human milk volume per day tended to increase during lactation. The mean volume to the 3rd month of lactation was 643m1 for primiparae and 654m1 for multiparae, and it was 647 $\pm$ 182m1 for both of them. The mean volume to the 5th month of lactation was 648m1 for primiparae and 668m1 for multiparae, and it was 658$\pm$186$m\ell$ for both of them. The peak volume was observed at the 1st month of lactation in 8 women of 15 lactating women, that is, 53.3% . The high distributions of the individual mean volume to the 5th month were found 550~650$m\ell$(40.0% ) and 650~750$m\ell$(26.7% ). and 13 women of 15 lactating women(86.6% ) were observed below 750m1. The number of feeding per day was 7.7~9.3 to the 5th month and the mean volume per feeding was 65~101$m\ell$. While the former tended to decreased, the latter increased during lactation. The human milk volume was correlated with the peak volume. but not with maternal age. weight before delivery. maternal height and birth weight. As mentioned above, the human milk volume of Koreans was about 658$\pm$ 186$m\ell$ and 86.6% of it was below 750$m\ell$. So the human milk volume, referred to as 800$m\ell$ in recommended dietary allowances for Koreans might be estimated over real amount. It is necessary to study according to regions. socioeconomic levels. maternal nutritional status and the early stage of lactation.

• STI Policy Review
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• v.6 no.2
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• pp.105-145
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• 2015

Science, technology and innovation (STI) is crucially important to eradicating poverty, and making advances in various areas such as agriculture, health, environment, transport, industry, and telecommunications. Therefore, it is vital to the overall socioeconomic development of nations. The indispensable role of STI in the competitive globalized economy led to several attempts to measure national STI capacities. The present study outlines STI capacity around three sets of capabilities: technological capabilities, social capabilities, and common capabilities. The Global Science, Technology and Innovation Capacity (GSTIC) index was developed to provide current evidence on the national STI capacities of the countries, and to improve the composite indicators used for such purposes. The GSTIC ranks a large number of countries (167) on the basis of their STI capacities and categories them into four groups: i.e. leaders, dynamic adopters, slow adopters, and laggards. For more meaningful assessment of the STI capacities of nations, it captures the achievement gaps of individual countries with the highest achiever. The study also provides ranking and achievement gaps of nations in the nine GSTIC pillars: technology creation, R&D capacity, R&D performance, technology absorption, diffusion of old technologies, diffusion of recent innovations, exposure to foreign technology, human capital, and enabling factors. A more detailed analysis of the strengths and weaknesses in different pillars of STI capacity of ten selected countries is also provided. The results show that there are significant disparities among nations in STI capacity and its various aspects, and developing countries have much to catch-up with the developed nations. However, different countries may adopt different strategies according to their strengths and weaknesses. Useful insight into the strengths and weaknesses of the national STI capacities of different countries are provided in the study.

• Journal of the Korean Society of School Health
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• v.29 no.3
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• pp.149-155
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• 2016

Purpose: The purpose of this study was to identify the influence of cell phone addiction on communication skills and the interpersonal relationship ability of adolescents. Methods: The researcher recruited 751 high school students to assess their general characteristics, communication skills, cell phone addiction and interpersonal relationship ability. Data were collected from June 30 to July 14 in 2014 using copies of a structured self report questionnaire. The collected data were analyzed with descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient and linear multiple regression using the SPSS/WIN 21.0 IBM program. Results: Of the students, 3.5% reported they were addicted users, and 7.6% reported they were heavy users. Results from multiple regression analysis showed that cell phone addiction did not have any influence on communication skills of the adolescents. However, cell phone addiction mostly affected the interpersonal relationship ability of the adolescents (${\beta}=.24$, p<.001). Poor school performance (${\beta}=.17$, p<.001) and low socioeconomic status (${\beta}=.12$, p<.05) were also related to the interpersonal skills of the adolescents. These variables explained 8.3% of the variance in the interpersonal skills of the adolescents. Conclusion: These results suggest that cell phone addiction has a negative influence on the development of the interpersonal relationship ability of adolescents. The findings of this study are expected to provide basic data about the influence of cell phone addiction on the interpersonal relationship ability of adolescents. Therefore, cell phone addiction treatment programs for adolescents need to include contents related to interpersonal relationship ability.

• Journal of the Korean Society of School Health
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• v.28 no.2
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• pp.79-88
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• 2015

The purpose of the study was to investigate mental health and mental health-related factors of adolescents with allergic diseases. Methods: The subjects were 72,060 middle and high school students, the data of whom were extracted from the 2014 Korean Youth' Risk Behavior Web-based Survey. Allergic diseases included asthma, allergic rhinitis and eczema. Mental health was measured by indicators such as perceived stress, depression, and suicidal ideation. To compare the mental health of adolescents who have allergic diseases with that of those who don't, the study used ${\chi}^2-test$ and calculated odds ratio (OR) and 95% confidence interval (CI). In addition, the study used ${\chi}^2-test$and multiple logistic regression, calculating OR and 95% CI, to analyze the association between mental health and allergic diseases and other variables. Results: Of 72,060 adolescents who participated in the study, 51.6% had allergic diseases(asthma 9.2%, allergic rhinitis 32.2%, eczema 23.9%). And 37.1% reported perceived stress, 26.6% depression, and 13.1% suicidal ideation. The adolescents with allergic diseases, compared to the adolescents without allergic diseases, were 1.26 times, 1.28 times, and 1.29 times more likely to experience perceived stress, depression, and suicidal ideation, respectively. The mental health-related factors of adolescents with allergic diseases were school type, sex, socioeconomic status, and academic performance. Conclusion: The adolescents with allergic diseases had poorer mental health than the adolescents without the diseases. Further studies should be done to verify this. And based on the study's findings, school-based intervention programs for mental health of adolescents with allergic diseases need to be developed.

• International Journal of Computer Science & Network Security
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• v.22 no.5
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• pp.175-181
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• 2022

COVID-19 is an acute respiratory syndrome that affects the host's breathing and respiratory system. The novel disease's first case was reported in 2019 and has created a state of emergency in the whole world and declared a global pandemic within months after the first case. The disease created elements of socioeconomic crisis globally. The emergency has made it imperative for professionals to take the necessary measures to make early diagnoses of the disease. The conventional diagnosis for COVID-19 is through Polymerase Chain Reaction (PCR) testing. However, in a lot of rural societies, these tests are not available or take a lot of time to provide results. Hence, we propose a COVID-19 classification system by means of machine learning and transfer learning models. The proposed approach identifies individuals with COVID-19 and distinguishes them from those who are healthy with the help of Deep Visual Embeddings (DVE). Five state-of-the-art models: VGG-19, ResNet50, Inceptionv3, MobileNetv3, and EfficientNetB7, were used in this study along with five different pooling schemes to perform deep feature extraction. In addition, the features are normalized using standard scaling, and 4-fold cross-validation is used to validate the performance over multiple versions of the validation data. The best results of 88.86% UAR, 88.27% Specificity, 89.44% Sensitivity, 88.62% Accuracy, 89.06% Precision, and 87.52% F1-score were obtained using ResNet-50 with Average Pooling and Logistic regression with class weight as the classifier.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.210-220
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• 2023

Recently, smart wearable products, including electromyography (EMG) measurement devices and clothing, have been developed to monitor users' exercise levels, muscle activation, and muscle balance more effectively during fitness activities. However, technical and socioeconomic barriers, such as flexibility and durability, still pose challenges in terms of comfort, ease of wear, and wearability of smart clothing, which includes devices and circuits. To address these issues, this study developed a wearable EMG device integrated with clothing to collect valid EMG signals from desired muscles while maintaining comfort, functionality, and ease of wear. After deriving a combined structure that could stably position the wearable device within the clothing, a prototype was manufactured and evaluated for fit, compression, comfort, and exercise comfort test by ten participants (height = 176.2 cm, weight = 76.4 kg, chest circumference = 101.2 cm). The study found that the prototype had smaller circumferences around the chest, waist, and abdomen compared to commercial products, resulting in lower ratings for wearing comfort and ease of wear. However, the prototype received high ratings for fitting, pressure, and the exercise comfort test. Valid signals were obtained when the EMG device was combined to the prototype for the rectus femoris muscle, indicating stable positioning of the device during exercise.

• Journal of Ocean Engineering and Technology
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• v.38 no.2
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• pp.64-73
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• 2024

Oil spills pose significant threats to marine ecosystems, human health, socioeconomic aspects, and coastal communities. Accurate real-time predictions of oil slick transport along coastlines are paramount for quick preparedness and response efforts. This study used an open-source OpenOil numerical model to simulate the fate and trajectories of oil slicks released during the 2007 Hebei Spirit accident along the Korean coasts. Six combinations of input parameters, derived from a five-day met-ocean dataset incorporating various hydrodynamic, meteorological, and wave models, were investigated to determine the input variables that lead to the most reasonable results. The predictive performance of each combination was evaluated quantitatively by comparing the dimensions and matching rates between the simulated and observed oil slicks extracted from synthetic aperture radar (SAR) data on the ocean surface. The results show that the combination incorporating the Hybrid Coordinate Ocean Model (HYCOM) for hydrodynamic parameters exhibited more substantial agreement with the observed spill areas than Copernicus Marine Environment Monitoring Service (CMEMS), yielding up to 88% and 53% similarity, respectively, during a more than four-day oil transportation near Taean coasts. This study underscores the importance of integrating high-resolution met-ocean models into oil spill modeling efforts to enhance the predictive accuracy regarding oil spill dynamics and weathering processes.

• The Journal of Information Systems
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• v.33 no.3
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• pp.187-205
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• 2024

Purpose A prediction model for occupational injuries can support more proactive, efficient, and effective policy-making. This study aims to develop a model that predicts the severity of occupational injuries, classified into 15 disability grades in South Korea, using machine learning techniques applied to COMWEL data. The primary goal is to improve prediction accuracy, offering an advanced tool for early intervention and evidence-based policy implementation. Design/methodology/approach The data analyzed in this study consists of 290,157 administrative records of occupational injury cases collected between 2018 and 2020 by the Korea Workers' Compensation & Welfare Service, based on the 'Workers' Compensation Insurance Application Form' submitted for occupational injury treatment. Four machine learning models - Decision Tree, DNN, XGBoost, and LightGBM - were developed and their performances compared to identify the optimal model. Additionally, the Permutation Feature Importance (PFI) method was used to assess the relative contribution of each variable to the model's performance, helping to identify key variables. Findings The DNN algorithm achieved the lowest Mean Absolute Error (MAE) of 0.7276. Key variables for predicting disability grades included the severity index, primary disease code, primary disease site, age at the time of the injury, and industry type. These findings highlight the importance of early policy intervention and emphasize the role of both medical and socioeconomic factors in model predictions. The academic and policy implications of these results were also discussed.

• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.642-649
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• 2013

This study evaluated the efficacy of information and self-interpretive media that provide information on park environment using self-administered visitor survey to the Dadohaehaesang National Park, Korea. Excluding missing and unreliable responses, 205 valid responses were used for the analysis. Socioeconomic status and visiting behavior of the visitors to the Dadohaehaesang National Park were similar to those to other Korean national parks. Results showed that, of the self-interpretive media, 'Information board of park use and resources' were most frequently used (87.7%), followed by 'Interpretive label of woody plant,' and 'Bulletin boards for information and enlightenment.' 'Guided interpretation' was used less than 40% of the visitors. Visitors also highly rated the importance of the media (higher than 4.0 on average out of 5 point Liker scale question). The average performance rate was 3.82, suggesting that visitors were satisfied on the self-interpretive media. Visitors responded that 'Information board of park use and resources' and 'Bulletin boards for information and enlightenment' were not useful and, therefore, should be amended and managed to improve the self-interpretability of the media.