• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.141-149
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• 2013

We present methods for studying the log-density ratio that enables the selection of the predictors and the form to be included in the logistic regression model. Under bivariate normal distributional assumptions, we investigate the form of the log-density ratio as a function of two predictors. If two covariance matrices are equal, then the crossproduct and quadratic terms are not needed. If the variables are uncorrelated, we do not need the crossproduct terms, but we still need the linear and quadratic terms. We also explore other conditions in which the crossproduct and quadratic terms are not needed in the logistic regression model.

• Fire Science and Engineering
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• v.33 no.6
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• pp.72-79
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• 2019

Through this study, we developed a model for predicting chemical accidents lead to casualties. The model was derived from the logistic regression analysis model and applied to the variables affecting the accident. The accident data used in the model was analyzed by studying the statistics of past chemical accidents, and applying independent variables that were statistically significant through data analysis, such as the type of accident, cause, place of occurrence, status of casualties, and type of chemical accident that caused the casualties. A significance of p < 0.05 was applied. The model developed in this study is meaningful for the prevention of casualties caused by chemical accidents and the establishment of safety systems in the workplace. The analysis using the model found that the most influential factor in the occurrence of casualty in accidents was chemical explosions. Therefore, there is an urgent need to prepare countermeasures to prevent chemical accidents, specifically explosions, from occurring in the workplace.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.71-76
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• 2018

The aim of this study was to evaluate the association between obesity and periodontal diseases in Korea adults. The date from the 2015 Korean National Health and Nutrition Survey were used, and 4,827 subjects over 19 years were included in the analysis. Periodontal disease was assessed using the Community Periodontal Index. Obesity was measured according to body mass index. Odd ratios (ORs) were estimated using binary logistic regression analysis model. The stratification variables were smoking and diabetes, and also adjusted for sex, age, and education level. The adjusting variables included sex, age, and education level. The ORs of obesity for periodontal disease were 0.78 (95% CI = 0.51-1.22) for the category of <18.5 of BMI and 1.29 (95% CI = 1.11-1.49) for the ${\geq}25$ BMI category (both compared to the 18.5 to 24.9 category). In a subgroup analysis, the OR of BMI among those who were both non-smoking and no diabetes was 1.20 (95% CI = 1.02-1.48) for those with BMI levels ${\geq}25$. This study implies that obesity intolerance may be an independent risk factor for periodontal diseases. Obesity should also be considered when managing periodontal disease to improve oral health.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.11 s.158
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• pp.1581-1588
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• 2006

The effects of removal of lignin or hemicellulose on the cottonizing and pulping characteristics of kenaf fiber were studied by comparing the conditions of non-cellulosic material contents, fiber lengths and dyeability. And the effects of lignin or hemicellulose on dyeability of the kenaf fiber using CI Direct Green 26 and CI Direct Red 81 were investigated. The results were as follows. The lignin contents decreased and the kenaf fiber became shorter and finer as the reaction time with sodium chlorite increased. The hemicellulose could be removed by treating sodium hydroxide solution to the fiber from which the lignin partly removed. The 80% of hemicellulose could be removed by 5% of sodium hydroxide solution in 5 minutes. But if lignin were not removed at all, hemicellulose could not be removed. The fiber lengths proper for apparel were obtained after treating sodium chlorite for 10-20 minutes and those for pulping were obtained after treating sodium chlorite for 40 minutes. The kenaf fibers from which lignin and hemicellulose partly removed were dyed with CI Direct Green 26 and CI Direct Red 81. Their dyeability increased as the removal rates of lignin increased. The ${\Delta}E$ values of kenaf fiber dyed with CI Direct Green 26 were lower than CI Direct Red 81.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.436-448
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• 2020

This study aims to determine the effect of e-cigarettes on oral health by investigating the association between the use of different tobacco products and oral health among Korean adults aged 19 years and older. Data from the 2017 Community Health Survey were used for the study. Respondents were divided into four groups: non-smokers, cigarette smokers, e-cigarette smokers, and users of both products. A sample of 228,357 respondents was selected for analysis. Twenty-four questionnaires with missing values (non-response or refusal) were excluded from the sample. A regression analysis was performed with oral as the dependent variable. A multivariate regression analysis showed a significant difference between cigarette smokers and users of both products when compared to the non-smokers. However, e-cigarette users showed a significant when the variables were correlated with age and gender. There was no significant difference in other dependent variables in a multivariate regression analysis. The results of the study indicated no association between e-cigarette use and oral health. More research is needed on factors such as amount and intensity of e-cigarette use.

• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.819-827
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• 2009

This study was conducted to investigate the relationship between the sociodemographic factors and the Korean consumers palatability evaluation grades with Hanwoo sensory evaluation data. The dichotomy logistic regression model and the multinomial logistic regression model are fitted with the independent variables such as the consumer living location, age, gender, occupation, monthly income, and beef cut and the the palatability grade as the dependent variable. Stepwise variable selection procedure is incorporated to find the final model and odds ratios are calculated to find the associations between categories.

• Journal of the Korean Data and Information Science Society
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• v.25 no.2
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• pp.373-384
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• 2014

Data mining is to clarify pattern or correlation of mass data of complicated structure and to predict the diverse outcomes. This technique is used in the fields of finance, telecommunication, circulation, medicine and so on. In this paper, we selected risk factors of respiratory diseases in the field of medicine. The data we used was divided into respiratory diseases group and health group from the Gyeongsangbuk-do database of Community Health Survey conducted in 2012. In order to select major risk factors, we applied data mining techniques such as neural network, logistic regression, Bayesian network, C5.0 and CART. We divided total data into training and testing data, and applied model which was designed by training data to testing data. By the comparison of prediction accuracy, CART was identified as best model. Depression, smoking and stress were proved as the major risk factors of respiratory disease.

• Journal of Nutrition and Health
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• v.40 no.sup
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• pp.39-49
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• 2007

본 논문은 미국 의학연구소(US Institute of Medicine, IOM)와 미국 농무성의 식이지침 자문위원회(USDA Advisory Committee on Dietary Guidelines, DG)에서 발표한 권위 있는 종설 들과 미국 영양사협회 학술지를 포함하여 여러 학술지에 발표된 의미 있는 종설 들의 내용을 종합한 것으로 일부의 내용은 그들의 의견을 그대로 반영하였다. 당은 단당류와 이당류를 말하며 당에는 포도당, 과당, 갈락토오즈, 맥아당, 서당과 유당이 포함된다. 당의 식품급원으로는 고과당 옥수수시럽, 사탕수수, 꿀, 사탕수수, 맥아시럽 등이 있다. 당은 미국 식약청에서 일반적으로 안전하다고 인식(generally recognized as safe, GRAS)되고 있다. 당은 에너지를 공급하며, 정신적인 만족감을 부여하는 기능을 가지고 있다. 대부분의 과일과 유제품은 당을 많이 함유하고 있으며, 건강한 식사를 구성하는 식품으로 섭취되고 있다. 당은 또한 조리와 가공과정에서 식품의 맛과 기능적인 면을 향상시키기 위해 첨가되기도 한다. 당은 영양밀도가 높은 식품/음료의 기호성(palatability)를 향상시키므로, 감미료들은 건강한 식사가 되도록 도와줄 수 있다. 그러나 첨가당의 섭취가 증가되면 식사의 영양밀도가 감소하는 가능성에 대한 우려가 있다. 여러 연구에 의하면 첨가당의 섭취가 총 열량 섭취의 25% 이상이 되면 식품의 영양밀도 감소가 나타날 수 있다고 보고하고 있다. 한국에서 추정된 당의 섭취량은 이것보다는 매우 낮은 수준이다. 선진국들에서 당의 섭취가 건강에 부정적인 영향을 줄 수 있다는 가능성에 대해서는 많은 논란이 되고 있다. 그러나 적절한 양을 섭취하는 범위에서 당의 섭취 자체만으로는 비만, 당뇨병, 대사증후군과 고콜레스테롤혈증의 위험이 증가되지 않는다는 과학적인 연구보고들이 있다. 그러므로 IOM은 "여러 자료에 근거하여, 충치, 행동적인 문제, 암, 비만의 위험성과 고지혈증의 위험성에 있어서 총 당과 첨가당에 대한 상한섭취량(tolerable upper limit)을 설정하는 것에 대한 증거가 불충분하다"고 결론을 내리고 있다.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1323-1331
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• 2018

The purpose of the study was to determine the general characteristics that affect strokes caused by smoking, to provide basic data and political grounds for preventing strokes. Data were used from the 6th (2015) of the National Health and Nutrition Survey. Among the study participants were 2,146 smokers and 132 strokers. Data were analyzed using SPSS ver. 21.0. The findings of the study were as follows: strokes increased the odds ratio 1.7 times(p<0.001) when smoking was performed, and the risk factors for strokes caused by smoking were statistically significant in age(p=0.008, p=0.10), education level(p=0.003, p=0.008), hypertension(p<0.001), and subjective health conditions(p=0.008). Therefore, it is necessary to develop health education contents using smart devices and a consistent national health policy to reduce the occurrence and risk of stroke.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.845-854
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• 2016

Sentiment analysis or opinion mining is a technique of text mining employed to identify subjective information or opinions of an individual from documents in blogs, reviews, articles, or social networks. In the literature, only a problem of binary classification of ratings based on review texts in an online review. However, because there can be positive or negative reviews as well as neutral reviews, a multi-class classification will be more appropriate than the binary classification. To this end, we consider the multi-class classification of ratings based on review texts. In the preprocessing stage, we extract words related with ratings using chi-square statistic. Then the extracted words are used as input variables to multi-class classifiers such as support vector machines and proportional odds model to compare their predictive performances.