• The Korean Journal of Emergency Medical Services
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• v.28 no.1
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• pp.21-34
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• 2024

Purpose: This study aimed to observe change in factors over time in the first cohort of the 2018 Children and Adolescent Panel Middle School. In addition, this study attempted to examine the causal relationship and influence between variables by setting a time gap between independent and dependent variables. Methods: Frequency and descriptive statistical analyses were conducted to determine the general characteristics of the study participants. Hierarchical regression analysis was conducted to analyze the effects of smartphone dependence on health, sleep quality, and depression. After inputting the control variables (Model 2), the influence of the variables was identified based on the input model. Results: Smartphone dependence positively impacted depression in both male and female students and negatively impacted sleep and health. Conclusion: Smartphones are closely associated with teenagers' lives. Additionally, as adolescents experience various psychological anxieties owing to rapid physical changes, there are concerns that psychological dependence may increase, considering that adolescence is the most emotionally unstable period. Therefore, the results of this study consistently prove that smartphone dependence has a causal relationship with emotion-related variables, such as emotional stress, depression, and anxiety.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.2
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• pp.113-119
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• 2024

Existing reinforced concrete buildings with seismically deficient column details affect the overall behavior depending on the failure type of column. This study aims to develop and validate a machine learning-based prediction model for the column failure modes (shear, flexure-shear, and flexure failure modes). For this purpose, artificial neural network (ANN), K-nearest neighbor (KNN), decision tree (DT), and random forest (RF) models were used, considering previously collected experimental data. Using four machine learning methodologies, we developed a classification learning model that can predict the column failure modes in terms of the input variables using concrete compressive strength, steel yield strength, axial load ratio, height-to-dept aspect ratio, longitudinal reinforcement ratio, and transverse reinforcement ratio. The performance of each machine learning model was compared and verified by calculating accuracy, precision, recall, F1-Score, and ROC. Based on the performance measurements of the classification model, the RF model represents the highest average value of the classification model performance measurements among the considered learning methods, and it can conservatively predict the shear failure mode. Thus, the RF model can rapidly predict the column failure modes with simple column details.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.592-597
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• 2020

Currently, river survey data is mainly performed by acquiring longitudinal and cross-sectional data of rivers using total stations or the GNSS(Global Navigation Satellite System). There is not much research that addresses the use of LiDAR(Light Detection and Ranging)systems for surveying rivers. This study evaluates the applicability of using LiDAR data for surveying rivers The Ministry of Land, Infrastructure and Transport recently launched a drone-based river fluctuation survey. Pilot survey projects were conducted in major rivers nationwide. Studies related to river surveying were performed using the ground LiDAR(Light Detection And Ranging)system.Accuracy was ensured by extracting the linearity of the object and comparing it with the total station survey performance. Data on trees and other features were extracted to generate three-dimensional geospatial information for the point-cloud data on the ground.Deviations were 0.008~0.048m. and compared with the results of surveying GNSS and the use of drone LiDAR data. Drone LiDAR provided accurate three-dimensional spatial information on the entire target area. It was able to reduce the shaded area caused by the lack of surveying results of the target area. Analyses such as those of area and slope of the target sites are possible. Uses of drones may therefore be anticipated for terrain analyses in the future.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.256-266
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• 2014

Purpose : This study was to explore the long-term effects of breast cancer prevention volunteering on self-efficacy, depression, and posttraumatic growth among survivors with breast cancer. Methods: This pilot study utilized a longitudinal design. Participants were 14 women with breast cancer who participated in the breast cancer prevention educational program The data were collated between February and August in 2013. Self-report questionnaires were used to measure the self-efficacy for self-management of breast cancer, depression, and posttraumatic growth at pre-education(T0), 1 month(T1), 3 months(T2), and 6 months(T1) post-education. A generalized estimating equation regression model was used to identify the effects. Results: The scores of self-efficacy increased significantly at T1(${\chi}^2$=5.56, p=.0l8) and D(${\chi}^2$=4.56, p=.033) compared with T0. Depression and posttraumatic growth remained stable with fairly good levels throughout the 6-month period. Conclusion: The results of this study suggest that breast cancer prevention volunteering in survivors with breast cancer can be effective for enhancing their self-efficacy and maintaining psychological well-bang. Also the study showed that such volunteering activity could be a useful program not only for the general public but also for breast cancer survivors.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.513-522
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• 2020

The purpose of this study is to analyze the auto-regression effect between the elderly's assets and depression and life satisfaction, and to approach the influence of assets and depression on the elderly's life from a longitudinal perspective. For this purpose, the data for the 9th year (2014), 11th year (2016), and 13th year (2018) of the Korea Welfare Panel were used. As a result of the analysis, First, the assets, depression and life satisfaction of the elderly have a lasting effect on the passage of time, and the assets, depression and life satisfaction of the previous point in time (B=.694, B=.725, p<.001), depression (B=.258, B=.331 and p<.001) and life satisfaction (B=.264, B=.265, p<.001). Second, cross-recursion coefficients show how the relationship between the assets of the elderly and depression and the satisfaction of life affects each other over time, and the assets of the older person at the previous point in time (B=.010, B=.011, p<.001), the assets of the older persons at previous times are subsequently satisfied with their lives (B=.128, B=.124, p<.001). Based on the results of the above analysis, it is necessary to support the elderly's asset management service and education to prevent depression, such as continuous asset utilization education.

• Journal of Preventive Medicine and Public Health
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• v.32 no.3
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• pp.355-360
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• 1999

Objectives: This 3-year longitudinal study was conducted to evaluate the influence of self-rating health perception on health care utilization and all cause-death risk. Methods: The hypothesis was tested using a community-based samples, among which subjects 3,414 were interviewed in 1995, Self-rating health perception was assessed by single-item question. Three components of health care utilization amount(number of visits, number of medications, yearly health care expenses) per year were measured using medical insurance data during 3-year follow-up period among subjects in district health care insurance. There were 123 deaths from all causes among 3,085 subjects interviewed. Results: The results showed that those who had poor health perception revealed more increases in the amount of health care utilization than good health perception group (p<0.05). After adjusting for age and sex, the poor health perception group had higher death risk over 3 years than good health perception group(hazard ratio=1.88). but, after adjusting health care utility, supplementary, was not significant. Conclusion: These results suggest that self-rating health perception was associated with difference in health care utilization and all cause-death risk.

• Journal of the Korean Home Economics Association
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• v.43 no.10 s.212
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• pp.39-53
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• 2005

The present study tested a multivariate model of direct and indirect influences of family Socioeconomic Status (SES) on children's early reading skills at kindergarten entry. The data used here are from one of the largest national databases in the USA, the Early Childhood Longitudinal Study-Kindergarten cohort (ECLS-K). Utilizing structural equation modeling, the results revealed that a number of factors within parental characteristics, home practices, and SES come together to influence children's early reading skills. SES operated primarily indirectly through home literacy activities and also directly in influencing reading. In addition, parental beliefs about kindergarten readiness mediated the relation between SES and home literacy activities. Thus, SES influenced early reading directly and indirectly, through home literacy activities, and simultaneously, through parental beliefs, which in turn, were associated with home literacy activities that were directly associated with children's reading. The findings emphasized the multiple pathways through which SES is associated with children's reading and the need to search for other mediators of SES influence.

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.655-664
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• 2018

The riverbed material survey is to investigate the particle size distribution, specific gravity, porosity, etc. as basic data necessary for river channel plan such as calculation of sediment transport and change of river bed. In principle, the survey spots are 1 km interval in the longitudinal direction of the river and 3 points or more in the 1 cross section. Therefore, depending on longitudinal length of the river to be investigated, the number of surveyed sites is very large, and the time and cost for the investigation are correspondingly required. This study is to compare the particle size analysis method with the volumetric method and the image analysis method in work efficiency and cost and to examine the applicability of the image analysis method. It was confirmed that the diameter of the equivalent circle converted by the image analysis method can be applied to the analysis of bed material particle size. In the gravel stream with a particle size of less than 10 cm and a large shape factor, the analytical result of the bed material by the image analysis method is accurate. However, when the shape factor decreases as the particle size increases, the error increases. In addition, analysis results of the work efficiency and cost of the volume method and the image analysis method showed a reduction of about 80%.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.435-443
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• 1999

This study was undertaken to investigate the growth change of genial angle and interrelationship between the growth change of gonial angle and IMPA in the longitudinal data from 7 years to 15 years. By analyzing the serial lateral cephalograms or 15 males and 19 females of 7 years old to 15 yens old who had no abnomality in growth and development and no history of orthodontic treatment, the following conclusion were obtained. 1. Genial angle gradually decreased with aging in 25 children and in 9 children increased or maintained. 2. There was a tendency that children who decreased genial angle with aging showed gradual increase of IMPA and children who increased or maintained gonial angle with aging showed decrease of IMPA. 3. There was a tendency that regardless of the change of gonial angle, interincisal angle decreased with aging.

• Korean Journal of Social Welfare
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• v.67 no.2
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• pp.137-159
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• 2015

This longitudinal study examined the influence of substandard housing conditions and housing affordability on physical and mental health. Using data from the Korea Welfare Panel Study, this study followed 8,583 adults who continued to participate in the survey from 2009 to 2013. Multivariate analyses involved linear and logistic regression models with the hybrid method that incorporates both fixed and random effects. Results show that substandard housing conditions and excess housing cost burden had significant adverse effects on adults' mental health (e.g., depressive symptoms). About one fourth of the entire sample and one third of those in poverty reported having lived in substandard housing conditions. Additionally, nearly one fourth of those in poverty reported having experienced excess housing cost burden, which is 4 times greater than that of the entire sample. Our findings show that a substantial proportion of individuals, particularly among the poor, have a difficulty in accessing to decent, affordable housing, and that housing assistance may have additional benefits of improving the mental health of individuals with housing issues.