• Journal of Korea Water Resources Association
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• v.51 no.3
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• pp.263-272
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• 2018

For the design of hydraulic structures, the design flood discharge corresponding to a specific frequency is generally used by using the design storm calculated according to the rainfall-runoff relationship. In the past, empirical equations such as rational equations were used to calculate the peak flow rate. However, as the duration of rainfall is prolonged, the outflow patterns are different from the actual events, so the accuracy of the temporal distribution of the probability rainfall becomes important. In the present work, Huff's quartile method is used for the temporal distribution of rainfall, and the third quartile is generally used. The regression equation for Huff's quadratic curve applies a sixth order polynomial equation because of its high accuracy throughout the duration of rainfall. However, in statistical modeling, the regression equation needs to be concise in accordance with the principle of simplicity, and it is necessary to determine the regression coefficient based on the statistical significance level. Therefore, in this study, the statistical significance test for regression equation for temporal distribution of the Huff's quartile method, which is used as the temporal distribution method of design rainfall, is conducted for 69 rainfall observation stations under the jurisdiction of the Korea Meteorological Administration. It is statistically significant that the regression equation of the Huff's quartile method can be considered only up to the 4th order polynomial equation, as the regression coefficient is significant in most of the 69 rainfall observation stations.

• Journal of Nutrition and Health
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• v.49 no.6
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• pp.482-494
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• 2016

Purpose: The objective of the present study was to evaluate nutrient and food group intakes in Korean adults according to energy intake from eating-out. Methods: This study was a cross-sectional study based on the 2013~2014 Korea National Health and Nutritional Examination Survey, and study subjects were 5,186 males (2,151) and females (3,035) aged 19~64 years. Energy intake from eating-out was analyzed using the 24-hour dietary recall method, and groups were classified by quartile according to energy intake from eating-out. Results: Subjects who had more energy intake from eating-out tended to be younger, highly educated, have a higher income, and have higher alcohol consumption. Total energy intake and fat intake density of the highest quartile group of energy intake from eating-out were higher than those of the other groups. However, fiber, vitamin $B_1$, calcium, phosphorus, potassium, and iron intake density levels were significantly lower in the highest quartile group of energy intake from eating-out. The highest quartile group of energy intake from eating-out consumed significantly more meat and beverages compared to the other groups. In addition, regarding diet quality (Index of nutritional quality), significantly lower vitamin $B_1$, calcium, phosphorus, and iron levels were observed in the highest quartile group of energy intake from eating-out compared to those in the other groups. Conclusion: In conclusion, in Korean adults, consumption of eating-out decreased dietary quality, including vitamin $B_1$, calcium, phosphorus, and iron levels. Further studies are needed to confirm these findings.

• Asia-Pacific Journal of Business
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• v.13 no.1
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• pp.185-195
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• 2022

Purpose - This study attempts to analyze the determinants of inventory turnover by applying quantile regression analysis. Design/methodology/approach - By selecting the gross margin, capital intensity, and sale surprise as the determinants of inventory turnover, we investigate their effects on inventory turnover at the several quartiles (10%, 25%, 50%, 75%, 90%) of inventory turnover with quantile regression analysis. Findings - The effects of gross margin and capital intensity on inventory turnover are different for each quartile. But the effects of sale surprise on inventory turnover are not different for each quartile. Research implications or Originality -This study is the first attempt to examine the effects of inventory turnover determinants on inventory turnover by applying quantile regression analysis was not employed in the prior studies. Thus, this study is meaningful in that it shows the possible way to review inventory management strategies that can be applied differently to the firms with different inventory turnover levels.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4429-4436
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• 2014

Background: Although the nutritional may exert effect on the breast cancer risk, it is not clear whether the role diet is the same in sedentary and physically active women. The aim of this study was to evaluate the association between fruit, vegetable and carbohydrate intake and the risk of breast cancer among Polish women considering their physical activity level. Materials and Methods: A case-control study was conducted that included 858 women with histological confirmed breast cancer and 1,085 controls, free of any cancer diagnosis, aged 28-78 years. The study was based on a self-administered questionnaire to ascertain physical activity, dietary intake, sociodemographic characteristics, reproductive factors, family history of breast cancer, current weight and high, and other lifestyle factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated in unconditional logistic regression analyses including a broad range of potential confounders. Results: With comparison of the highest vs lowest quartile of intake, strong significant associations were observed for total vegetables (OR=0.37, 95%CI=0.20-0.69 P for trend <0.01 and OR=0.53, 95%CI=0.29-0.96, P for trend <0.02), and total fruits (OR=0.47, 95%CI=0.25-0.87, P for trend <0.05 and OR=0.47, 95%CI=0.24-0.90, P for trend <0.02) among women characterized by the lowest and the highest quartile of physical activity. No associations were observed for total carbohydrate intake. Additional analysis showed a positive association for sweets and desert intake among women in the lowest quartile of physical activity (OR=3.49, 95%CI=1.67-7.30, P for trend <0.009) for extreme quartiles of intake comparing to the referent group. Conclusions: The results suggest that a higher consumption of vegetable and fruit may be associated with a decreased risk of breast cancer, especially among women who were low or most physically active throughout their lifetimes. These findings do not support an association between diet high in carbohydrate and breast cancer. However, a higher intake of sweets and deserts may by associated with an increased risk of breast cancer among women who were less physically active.

• Korean Journal of Community Nutrition
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• v.6 no.2
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• pp.121-129
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• 2001

The purpose of this study was to estimate the prevalence and to identify risk factors of overweight among preschool children in Korea. The study subjects were 750 children, aged 2-6, attending child care centers in Korea. A measurement of the height and weight of the children, as well as collection of wide range of variables including general characteristics, and potential factors related with dietary habit for children and their parents, were conducted. Overweight was defined based on more than 110% of ideal body weight. A logistic regression analysis was adopted to identify the factors associated with overweight. Subjects were classified into three categories according to the obesity index : underweight(PIBW〈90%, n=34), normal(90%$\leq$PIBW〈110%, n=577), and overweight(PIBW$\geq$110%, n=139). The overall prevalence of overweight and underweight of the subjects were 21.3% and 4.0% of the boys and 15.5% and 5.1% of the girls respectively. Parent's obesity was associated with a higher risk of overweight on girls. Subjects o the third quartile(girls) and fourth quartile(boys) of income level had a substantially higher risk of overweight than did those in the first quartile. Fast eating, overeating, and food prejudice were also associated with an increased risk of overweight. The results of a logistic regression analysis showed that the eating habits and food preferences of the children were the most influencial factors on overweight. These finding may imply the importance of early stage nutrition education on rational dietary habit to prevent prevailing obesity of preschool in Korea.

• Journal of Preventive Medicine and Public Health
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• v.38 no.3
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• pp.325-329
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• 2005

Objectives : This study was performed to assess the association between high sensitivity C-Reactive Protein (hsCRP) and hypertension. Methods : We evaluated the relationship between hsCRP with hypertension and other cardiovascular risk factors, using a cross-sectional survey of 202 people over the age of 50, living in a rural area. A logistic regression analysis was used to study the association between hsCRP and hypertension. The hsCRP levels were divided in quartiles, and the odds ratios (OR), with 95% confidence intervals (95% CI), calculated, using the lowest quartile as a reference. Results : The subjects consisted of 37.1% men and 62.9% women, with a mean (SD) hsCRP level of $1.9({\pm}3.0mg/{\ell})$ . The overall prevalence of hypertension was 61.4%. The prevalence of hypertension according to the hsCRP quartile was not statistically significant. After adjustment for confounding variables, the prevalence of hypertension according to the subjects in the 2nd, 3rd and 4th hsCRP quartiles were 1.418 (95% CI=0.554-3.628), 1.124 (95% CI=0.392-3.214) and 0.892 (95% CI=0.312-2.547) times higher, respectively, compared to those in the 1st quartile. Conclusions : The results showed that the level of hsCRP was not a risk factor for hypertension among adults aged over 50 years, living in a rural area. A further study should be performed to find the association between hsCRP and hypertension.

• Journal of Preventive Medicine and Public Health
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• v.49 no.5
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• pp.260-274
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• 2016

Objectives: Previous epidemiological studies about oxidative stress and depression are limited by hospital-based case-control design, single-time measurements of oxidative stress biomarkers, and the small number of study participants. Therefore, in this study, we analyzed the association between biomarker of oxidative stress and depressive symptom scores using repeatedly measured panel data from a community-dwelling elderly population. Methods: From 2008 to 2010, a total of 478 elderly participants residing in Seoul, Korea, were evaluated three times. Participants underwent the Korean version of the Short Form Generic Depression Scale (SGDS-K) test for screening depression, and urinary malondialdehyde (MDA) levels were measured as an oxidative stress biomarker. We used a generalized estimating equation with a compound symmetry covariance structure to estimate the effects of oxidative stress on depressive symptom scores. Results: A two-fold increase in urinary MDA concentration was significantly associated with a 33.88% (95% confidence interval [CI], 21.59% to 47.42%) increase in total SGDS-K scores. In subgroup analyses by gender, a two-fold increase in urinary MDA concentration was significantly associated with increased SGDS-K scores in both men and women (men: 30.88%; 95% CI, 10.24% to 55.37%; women: 34.77%; 95% CI, 20.09% to 51.25%). In bivariate analysis after an SGDS-K score ${\geq}8$ was defined as depression, the third and the fourth urinary MDA quartiles showed a significantly increased odds ratio(OR) of depression compared to the lowest urinary MDA quartile (third quartile OR, 6.51; 95% CI, 1.77 to 24.00; fourth quartile OR, 7.11; 95% CI, 1.99 to 25.42). Conclusions: Our study suggests a significant association between oxidative stress and depressive symptoms in the elderly population.

• Journal of Nutrition and Health
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• v.39 no.3
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• pp.264-273
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• 2006

Elevated maternal plasma homocysteine concentrations have been associated with adverse pregnancy outcomes. Serum homocysteine levels may be affected by the MTHFR genotypes and the nutritional status of B vitamins including vitamin $B_2,\;B_6$, folate and vitamin $B_{12}$. We investigated whether postnatal growth measurements were influenced by maternal MTHFR genotypes and their mid-pregnancy serum vitamin B and homocysteine levels. In 130 pregnant women of 24-28 wks of gestation, the MTHFR genotypes, serum B vitamins and homocysteine concentrations were analyzed. Physical growth status was assessed in their offsprings by measuring height, weight, and head and chest circumferences from birth up to 24 months. Serum homocysteine levels were higher in the subjects with T/T genotype than those with the C/T or C/C. Heights and head and chest circumferences of offsprings from the T/T mothers were significantly lower than those from the C/C or C/T mothers only when the serum homocysteine levels were above the median. The mean height of offsprings from the T/T mothers was significantly lower than those from the C/C and C/T mothers. The mean weight and head circumferences of offsprings born from the mothers whose mid-term pregnancy PLP levels were in the lowest quartile was significantly lower than those from mothers in the highest quartile. Heights and head circumferences of offsprings from the T/T mothers were significantly lower than those from the C/C or C/T mothers only when the serum FAD levels were in the lowest quartile. These results suggest that postnatal growth up to 24 months may be influenced by the maternal C677T MTHFR genotypes, and mid-pregnancy serum homocysteine and vitamin B status.

• Journal of Nutrition and Health
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• v.39 no.8
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• pp.795-800
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• 2006

In order to examine nutritional and behavioral risk factors of atopic dermatitis (AD) in Korean preschoolers, we analyzed data on 144 children aged 3-6 years with AD and their 434 healthy counterparts. The data included breast-feeding history, current weight, food behaviors assessed by the Mini Dietary Assessment (MDA), food intake by a semi-quantitative food frequency questionnaire, and behavior problems by the Preschool and Kindergarten Behavior Scale (PKBS). Multivariate logistic regression analyses were performed after controlling for preschool location and child's age, gender and total energy intake, as appropriate. There was no group difference of child and household characteristics. Breastfeeding history was related to lower AD risk (OR = 0.63, 95% Cl = 0.40-0.99), yet no statistically significant association was found with overweight status. Regarding food behaviors, AD risk was lower in children who drank milk at least one cup per day (OR = 0.52, 95% Cl = 0.35-0.78) and had regular meals (OR = 0.62, 95% Cl =0.42-0.92). Moreover, there were lower risks of AD in the second (OR =0.48, 95% Cl = 0.28-0.82) and the highest (OR = 0.55, 95% Cl = 0.32-0.94) intake quartiles as compared with the lowest quartile of kimchi intake. Similarly, AD risk was lower in the highest quartile of rice (OR = 0.51 Cl = 0.28-0.93) and the second quartile of fruit (OR =0.45, 95% Cl = 0.25-0.82) intakes. AD children had more problems in social interaction (OR = 1.97,95% Cl = 1.26-3.07) and independence (OR = 1.60, 95% Cl = 1.01 -2.54) measures than the healthy controls. Likewise, AD children tended to show more problem behaviors such as anxiety (OR = 1.63, 95% Cl = 0.99-2.69). Our results suggest that nutritional and behavioral dimensions are related to AD risk, yet the case control study design may preclude generalization of these results.

• Journal of Korean Public Health Nursing
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• v.31 no.2
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• pp.376-388
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• 2017

Purpose: The triglyceride-to-high-density lipoprotein-cholesterol (TG/HDL-C) ratio is one of the main predictive indices for cardiovascular disease. This study was examined the relationship between TG/HDL-C ratio and metabolic syndrome (MetS) in male office workers. Methods: Secondary analysis was conducted to determine the risk between the TG/HDL-C ratio and MetS in male office workers. A total of 765 people underwent the 'regular workplace health checkups in 2014'. Among the subjects who were male and responded to the questionnaire and health lifestyle survey, 470 (61.4%) excluding those with missing and/or abnormal values were analyzed. The association between MetS, MetS components, and the TG/HDL-C ratio was examined by a Chi-square test, One-way ANOVA, Turkey post-hoc test and Logistic regression analysis. Results: The number of males with MetS was 70 (14.9%) and the number of MetS components increased with increasing TG/HDL-C ratio (p<.001). Logistic regression analysis with an adjustment for potential confounders revealed a 31.8 times higher odds ratio of the Quartile4 group for MetS than that of the Quartile1 group (p<.001). Conclusion: These results show that the likelihood of MetS, particularly the risk of MetS in the Quartile4, increases with increasing TG/HDL-C ratio.