• 한국노년학
• /
• v.30 no.4
• /
• pp.1311-1327
• /
• 2010

This study was conducted to identify the relationship between depression and subjective/objective health status, and to examine predicting factors on depression in the elderly in Korea. This study was a secondary analysis using the data of Korea National Health and Nutrition Examination Survey(VI-1) 2007. A total of 939 data from the subjects ≥60 years who completed health-related survey were used for analysis. Data were analyzed using SAS (version 9.1) PC program. Depression was identified in the 20.3% of the older subjects. Multiple logistic regression analysis showed that women (OR=2.04), senior high school graduation (OR=0.27) and lowermiddle household income (OR=2.83) were significant associating factors(p<0.05). After adjustment for socio-demographic factors, hypertension (OR=1.93) and asthma (OR=3.32) as objective health status, and stress (OR=7.27), limited activity in daily living due to fracture or joint injury (OR=6.59) and poor self-rate health (OR=1.64) as subjective health status were found as factors predicting depression in the elderly(p<0.05). According to the type of health status, the subjects who had chronic disease or perceived poor physical health were 5.94 times more likely to have disposition to depression than the subjects who had no chronic disease or perceived good physical health (p=0.001). These findings suggest that preventive education and intervention focus on preventing and managing chronic diseases such as hypertension, asthma, fracture and joint injury should be needed to decrease depression in the elderly.

• Journal of Industrial Convergence
• /
• v.21 no.8
• /
• pp.75-86
• /
• 2023

The purpose of this study was to provide basic data to increase happiness by verifying the mediating effect of career identity in the relationship between community consciousness, civic consciousness, career identity and happiness of high school students. Data analysis used data from the '2020 Generation Z Teenage Values Survey' conducted by the Korea Youth Policy Institute. Among the survey subjects, 2,959 out of 3,037 high school students who met the purpose of this study, excluding missing, were sampled and analyzed using the SPSS WIN 25.0 program. The analysis method used frequency analysis, descriptive statistical analysis, correlation analysis, and Bayron and Kenny's analysis methods to verify the mediating effect, and applied Sobel test techniques to analyze indirect effects and significance. The results of the study showed that, first, high school students' sense of community and citizenship increased their happiness. Second, career identity had a partial mediating effect in the relationship between community consciousness and happiness. Third, it shows a partial mediating effect of career identity in the relationship between citizenship and happiness. Based on this, this study is meaningful in that it suggests policy alternatives and practical programs to promote high school students' happiness.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.17 no.1
• /
• pp.229-249
• /
• 2022

This paper investigates machine learning models for predicting the designation of administrative issues in the KOSDAQ market through various techniques. When a company in the Korean stock market is designated as administrative issue, the market recognizes the event itself as negative information, causing losses to the company and investors. The purpose of this study is to evaluate alternative methods for developing a artificial intelligence service to examine a possibility to the designation of administrative issues early through the financial ratio of companies and to help investors manage portfolio risks. In this study, the independent variables used 21 financial ratios representing profitability, stability, activity, and growth. From 2011 to 2020, when K-IFRS was applied, financial data of companies in administrative issues and non-administrative issues stocks are sampled. Logistic regression analysis, decision tree, support vector machine, random forest, and LightGBM are used to predict the designation of administrative issues. According to the results of analysis, LightGBM with 82.73% classification accuracy is the best prediction model, and the prediction model with the lowest classification accuracy is a decision tree with 71.94% accuracy. As a result of checking the top three variables of the importance of variables in the decision tree-based learning model, the financial variables common in each model are ROE(Net profit) and Capital stock turnover ratio, which are relatively important variables in designating administrative issues. In general, it is confirmed that the learning model using the ensemble had higher predictive performance than the single learning model.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.4
• /
• pp.409-420
• /
• 2023

The purpose of this study is to analyze trends in the prevalence of dental caries and demand for dental caries treatment among children under 14 years old using Health Insurance Review and Assessment data. The analysis was conducted using treatment records from a random sample of approximately 1 million pediatric patients from a population that included all children and adolescents for each year from 2011 to 2020. In this study, the number of children diagnosed with K02 dental caries and the number of children receiving dental caries treatment across all ages have increased. However, the number of children aged 10 to 14 who received pulp treatment or extraction has decreased. In the National Survey of Children's Oral Health, the decay-missing-filled teeth index for 5- and 12-year-olds has stagnated or increased slightly, but the percentage of the population with active dental caries has decreased. Accessibility and local environments for dental caries treatment have generally improved compared to the past, but preventive dental care has stagnated over the past decade. Therefore, it is necessary to evaluate the effectiveness of oral health programs implemented in Korea to promote and prevent dental caries among children.

• Journal of Industrial Convergence
• /
• v.22 no.2
• /
• pp.143-151
• /
• 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
• /
• v.29 no.6
• /
• pp.639-652
• /
• 2009

This projects was carried out under the assumption that an appealing leadership program would lead to students' increased leadership abilities. This leadership program is comprised of 16 materials based on seven factors of leadership for the gifted and talented. More than 46% of the gifted and talented have a positive response to leadership program, and some of these gifted and talented students (14.7%) reacted negatively. According to the result of the T-Test, a survey about leadership of gifted and talented, there are meaningful differences between before and after implementing this leadership program (p<.01). Especially, the leadership quality of the gifted and talented improved effectively in communication skills(p<.01), individualized considerations(p<.01), and interpersonal skills(p<.05). But there aren't statistical differences between the primary school students and the middle school students except leadership total score(p<.05) and communication skills(p<.01). Comprehensively, the primary school students scored slightly higher than did middle school students on the seven factors of leadership. So, we need an effective guide in planning a leadership program for middle school students.

• Journal of Korea Water Resources Association
• /
• v.57 no.5
• /
• pp.321-332
• /
• 2024

Understanding the status of surface cover in riparian zones is essential for river management and flood disaster prevention. Traditional survey methods rely on expert interpretation of vegetation through vegetation mapping or indices. However, these methods are limited by their ability to accurately reflect dynamically changing river environments. Against this backdrop, this study utilized satellite imagery to apply the Random Forest method to assess the distribution of vegetation in rivers over multiple years, focusing on the Naeseong Stream as a case study. Remote sensing data from Sentinel-2 imagery were combined with ground truth data from the Naeseong Stream surface cover in 2016. The Random Forest machine learning algorithm was used to extract and train 1,000 samples per surface cover from ten predetermined sampling areas, followed by validation. A sensitivity analysis, annual surface cover analysis, and accuracy assessment were conducted to evaluate their applicability. The results showed an accuracy of 85.1% based on the validation data. Sensitivity analysis indicated the highest efficiency in 30 trees, 800 samples, and the downstream river section. Surface cover analysis accurately reflects the actual river environment. The accuracy analysis identified 14.9% boundary and internal errors, with high accuracy observed in six categories, excluding scattered and herbaceous vegetation. Although this study focused on a single river, applying the surface cover classification method to multiple rivers is necessary to obtain more accurate and comprehensive data.

• Journal of Preventive Medicine and Public Health
• /
• v.24 no.3 s.35
• /
• pp.363-372
• /
• 1991

We used the health screening data of some rural and urban residents to examine the cross-sectional association between leukocyte count and hypertension. The 206 male and 203 female rural residents were selected by multi-stage cluster sampling method in Kyungsan-Kun area of Kyungbuk province in 1985 and 600 urban residents were selected by the same sampling method as the rural residents in Daegu city of the same province in 1986 compatible with age-sex distribution of Daegu city of 1985 census, but of whom 384 actually responded. The rest of 600 were replaced by age and sex with those who were members of the medical insurance plan visiting the health management department of the university hospital to get the biannual preventive medical checkups. Excluded in the analysis were those having hypertensive history, diseases and extreme outlying values of the screening tests, leaving 373 rural and 571 urban residents. Leukocyte count was measured with ELT-8 Laser shadow method and the unit $cells/mm^3$, Blood pressures were determined with an aneroid sphygmomanometer with pre-standardized method and hypertensives were defined as those showing systolic blood pressure more than 140mmHg and/or diastolic blood pressure more than 90mmHg. Total residents pooled (N=944) showed a significant difference between hypertensives and normotensives ($6965.93{\pm}1997.01\;vs\;6490.61{\pm}1941.32,\;P=0.00$) and in rural residents was noted the similar significant difference (P=0.03). None of significant differences were noted in any stratum stratified by residency and sex. Compared to the lowest quintile of WBC, 2/5 quintile showed odds ratio 0.99 (95% Confidence interval, Ci 0.62-1.59), 3/5 quintile 1.41 (95% CI 0.90-2.21), 4/5 quintile 1.76 (95% CI. 1.14-2.72), and highest quintile 1.80 (1.15-2.82) in the total residents. Likelihood ratio test for linear trend for it indicated a significant trend ($X^2_{trend}=5.53,\;df=1,\;P<0.05$). There were no other significant odds ratios compared to the lowest quintile of WBC in strata stratified by residency and sex. The odds ratios in total residents which had showed significant odds ratios became nonsignificant and of reduced magnitude after controlling age, frequency of smoking and drinking with multiple logistic. regression. In each stratum, it changed magnitudes of odds ratios slightly and unstably. None of the trend tests showed any significant trend. These results suggest that the Friedman et al's finding of association between leukocyte count and hypertension may be due to an statistical type I error resulting from the data dredging in an exploratory study, in which more than 800 variables were screened as possible predictors of hypertension.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.17 no.1
• /
• pp.80-90
• /
• 2014

The objective of this research is to estimate the stand volume of Pinus koraiensis, by using the investigated volume and the information of remote sensing(RS), in the research forest of Kangwon National University. The average volume of the research forest per hectare was $307.7m^3/ha$ and standard deviation was $168.4m^3/ha$. Before and after carrying out 3 by 3 majority filtering on TM image, eleven indices were extracted each time. Independent variables needed for linear regression equation were selected using mean pixel values by indices. The number of indices were eleven: six Bands(except for thermal Band), NDVI, Band Ratio(BR1:Band4/Band3, BR2:Band5/Band4, BR3:Band7/Band4), Tasseled Cap-Greeness. As a result, NDVI and TC G were chosen as the most suitable indices for regression before and after filtering, and R-squared was high: 0.736 before filtering, 0.753 after filtering. As a result of error verification for an exact comparison, RMSE before and after filtering was about $69.1m^3/ha$, $67.5m^3/ha$, respectively, and bias was $-12.8m^3/ha$, $9.7m^3/ha$, respectively. Therefore, the regression conducted with filtering was selected as an appropriate model because of low RMSE and bias. The estimated stand volume applying the regression was $160,758m^3$, and the average volume was $314m^3/ha$. This estimation was 1.2 times higher than the actual stand volume of Pinus koraiensis.

• Korean Journal of Remote Sensing
• /
• v.29 no.5
• /
• pp.517-525
• /
• 2013

Time-series data of Normal Difference Vegetation Index (NDVI) obtained by the Moderate-resolution Imaging Spectroradiometer(MODIS) satellite imagery gives a waveform that reveals the characteristics of the phenology. The waveform can be decomposed into harmonics of various periods by the Fourier transformation. The resulting $n^{th}$ harmonics represent the amount of NDVI change in a period of a year divided by n. The values of each harmonics or their relative relation have been used to classify the vegetation species and to build a vegetation map. Here, we propose a method to estimate the annual amount of carbon absorbed on the forest from the $1^{st}$ harmonic NDVI value. The $1^{st}$ harmonic value represents the amount of growth of the leaves. By the allometric equation of trees, the growth of leaves can be considered to be proportional to the total amount of carbon absorption. We compared the $1^{st}$ harmonic NDVI values of the 6220 sample points with the reference data of the carbon absorption obtained by the field survey in the forest of South Korea. The $1^{st}$ harmonic values were roughly proportional to the amount of carbon absorption irrespective of the species and ages of the vegetation. The resulting proportionality constant between the carbon absorption and the $1^{st}$ harmonic value was 236 tCO2/5.29ha/year. The total amount of carbon dioxide absorption in the forest of South Korea over the last ten years has been estimated to be about 56 million ton, and this coincides with the previous reports obtained by other methods. Considering that the amount of the carbon absorption becomes a kind of currency like carbon credit, our method is very useful due to its generality.