• Journal of the Korean Data and Information Science Society
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• v.27 no.5
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• pp.1317-1325
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• 2016

The purpose of this paper is to explain the factors affecting the wage of the vocational high school graduates. We particularly examine the effectiveness of controlling sample selection bias by employing the Tobit model and Heckman sample selection model. The major results are as follows. First it is shown that the Tobit model and Heckman sample selection model controlling sample selection bias is statistically significant. Hence all the independent variables seem to be statistically consistent with the theoretical model. Second, gender was statistically significant, both in the probability of employment and the wage. Third, the employment probability and wage of Maester high school graduates were shown to be high compared to all other graduates. Fourth, the higher parent's income, the higher are both the employment probability and the wage. Finally, parents education level, high school grade, satisfaction, and a number of licenses were found to be statistically significant, both in the probability of employment and wages.

• Journal of the Korean Geographical Society
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• v.33 no.2
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• pp.325-338
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• 1998

본 연구에서는 시.공 복합적인 선형 점 자료를 대상으로 시간과 공간을 함께 고려했을 때 자료 내에 군집(cluster)-시.공 복합 군집(space-time cluster)-이 존재하는 가를 검증하는 방법에 대해 논의하고, 실제 교통사고지점의 분포자료를 분석하여 군집의 유무를 통계적으로 검증하였다. 통계 분석의 결과 다음과 같은 사실이 확인되었다. 첫째, Knox의 분할표 방법과 Mantel의 역수 변환을 이용한 일반화된 회귀분석방법 모두 임계 거리 및 임계 시간 간격의 선택이 분석결과에 영향을 미친다. 둘째, 이러한 임의성을 극복하기 위해 다양한 임계 거리 및 임계 시간 간격(혹은 부가 상수)에 대해 반복 실험한 결과, 일부 임계값의 조합에서 시간과 공간이 서로 독립적이라는 귀무가설을 기각할 수 있는 증거가 발견되었다. 셋째, 시.공 복합 군집의 파악에 가장 적합한 임계 거리와 임계 시간 간격은 공간적으로는 7000m, 시간적으로는 14일 혹은 21일이다. 마지막으로, 통계 분석과정에서 자료에 존재하는 중복 기록 사고들의 존재가 밝혀짐으로써 시.공 복합군집 검증이 탐험적 자료 분석(exploratory data analysis)의 도구로서 가지는 가치를 확인할 수 있었다.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.277-283
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• 2020

The purpose of this study was to identify the risk factors influencing stroke. The research method was used two-stage stratified cluster sampling using data from the National Health and Nutrition Survey (2016-2018). This study subjects performed a complex sample logistic regression analysis on adults aged 19 or older. Risk factors affecting stroke were shown as follows: in age groups, odds ratio were conformed when people are in their 70s, the rate is 8.861 times higher; when they are in their subjective health conditions, the odds ratio are 4.501 times higher in the bad groups; odds ratio was 3.158 times higher in the group diagnosed with hypertension and 1.598 times higher in the group diagnosed with diabetes. The result of this study found that chronic diseases such as high blood pressure and diabetes and the management of senior citizens are important because stroke is dangerous and can be managed through prevention.

• Journal of the Korean Data and Information Science Society
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• v.28 no.5
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• pp.1099-1107
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• 2017

In this study, we analyzed the determinants of wages of college graduates by using the data of "2014 Graduates Occupational Mobility Survey" conducted by Korea Employment Information Service. In general, wages contain two complex pieces of information about whether an individual is employed and the size of the wage. However, in many previous researches on wage determinants, sample selection bias tends to be generated by performing linear regression analysis using only information on wage size. We used the Heckman sample selection models for analysis to overcome this problem. The main results are summarized as follows. First, the validity of the Heckman's sample selection model is statistically significant. Male is significantly higher in both job probability and wage than female. As age increases and parents' income increases, both the probability of employment and the size of wages are higher. Finally, as the university satisfaction increases and the number of certifications acquired increased, both the probability of employment and the wage tends to increase.

• Journal of Industrial Convergence
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• v.18 no.3
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• pp.73-82
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• 2020

The purpose of this study was to explore sexual behaviors among adolescents in multicultural families in Korea. The data were obtained from the 15th Korea Youth Risk Behavior Survey 2019. Complex-sample descriptive statistics and the chi-square test were used for data analysis in SPSS 25. Among adolescents in multicultural families, 8.2% reported having sexual experience. Condoms were the most commonly used contraceptive method, and most adolescents received sex education at school. Their likelihood of sexual experience differed according to grade, academic achievement, economic status, residential area, perceived stress, and drinking and smoking experience (p<.001). The results of this study suggest that sex education should be conducted with appropriate consideration of the important factors associated with adolescents in multicultural families.

• Journal of the Korean Society of Groundwater Environment
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• v.2 no.2
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• pp.58-63
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• 1995

Cokriging was applied for the estimation of the water levels of the basal leachate and the surrounding groundwater at the Nanjido waste landfill area. When the groundwater level is estimated at the high relief area, it makes a good result to use the data of groundwater level and elevation simultaneously because groundwater level is correlated with topography. This study determined the best semivariogram model of 87 groundwater levels and 144 elevations through cross validation test, and produced the contour maps of groundwater levels using ordinary kriging and universal kiging. Two contour maps don't make big difference at the waste site because this area has a large number of groundwater level data. However, they show big difference at the upper left part of the study area because this area has high relief and a small number of sample data. Their difference is also found at the south area near the Han river. When the topography is considered for the both areas, the contour map of cokriging is thought to be closer to the real groundwater distribution than that of kriging.

• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.829-846
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• 2014

Using complex sample design, this article analyzes the difference between sex and age groups of mental health, physical activity, suffering lifestyle diseases, drinking, and smoking using the fifth Korea national health and nutrition examination survey data (2011-2012), and then analyzes the effect of mental health, physical activity, suffering lifestyle diseases, drinking, and smoking on EQ-5D, a measure of health-related quality of life. The results show that mental health, physical activity, suffering lifestyle diseases, drinking and smoking are statistically different among gender and age groups, and that age group, education level, suffering diabetes, recognizing stress, thinking suicide are statistically influential on EQ-5D.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.149-157
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• 2018

This study was conducted to analyze oral health conditions and behaviors of obese people over the age of 19 to identify relevant factors. Using the data of the 6th Korean National Health and Nutrition Examination Survey, 5,632 people were classified by body mass index(BMI). The relationship between drinking, smoking, and oral health status and behavior according to obesity index was analyzed by X2-test and logistic regression analysis. Results showed that men, 60s, low income, low education level and in marriage group were high in obesity. Obese people were related with higher prevalence of periodontal disease and perceived subjective oral health status to be worse. This study will contribute to the development of programs to improve oral health of obese adults. Therefore, it is necessary to induce motivation to improve oral health by regular education through development of customized oral education program for obese adults.

• Journal of Industrial Convergence
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• v.18 no.5
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• pp.70-76
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• 2020

The purpose of this study was to determine the dietary behavior of adolescents and to determine the association with allergic diseases according to dietary behavior. The data were obtained from the 15th Korea Youth Risk Behavior Survey 2019. Complex-sample descriptive statistics and the chi-square test were used for data analysis in SPSS. Adolescents diagnosed with asthma had a relationship with frequency of breakfast, fruit, soda, energy drink, sweet drink, fast food, vegetable and convenience store eating experience. Adolescents diagnosed with allergic rhinitis were associated with frequency of breakfast, fruit, soda, sweet drinks, vegetables, and milk. Adolescents diagnosed with atopic dermatitis were associated with soda, vegetables, milk, and convenience store eating experiences. Therefore, in the case of adolescents with allergic diseases, it is necessary to educate them on correct dietary behavior so that they can have correct habits.

• Journal of Industrial Convergence
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• v.18 no.5
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• pp.62-69
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• 2020

The purpose of this study was to investigate the relationship between serum vitamin E levels and the risk of allergic rhinitis among Koreans. This study is a secondary data analysis using big data from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII-3), which was conducted in 2018. Complex-sample descriptive statistics, t-test, ANOVA and odds ratio were used for data analysis in SPSS 25. The average serum vitamin E level among Koreans aged above 10 was 12.60 mg/L, and 15.9% had been diagnosed with of allergic rhinitis by a doctor. Lower serum vitamin E levels were significantly associated with the prevalence of allergic rhinitis (β=-0.05, p=.013). Therefore, efforts to prevent and manage allergic rhinitis among Koreans should incorporate regular monitoring of vitamin E level and ongoing research into antioxidants.