• Journal of Korea Water Resources Association
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• v.43 no.12
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• pp.1083-1091
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• 2010

Distributed hydrologic models typically require spatial estimates of precipitation interpolated from sparsely located observational points to the specific grid points. However, widely used estimation schemes fail to describe the realistic variability of daily precipitation field. We compare and contrast the performance of statistical methods for the spatial estimation of precipitation in two hydrologically different basins, and propose a two-step process for effective daily precipitation estimation. The methods assessed are: (1) Inverse Distance Weighted Average (IDW); (2) Multiple Linear Regression (MLR); (3) Climatological MLR; and (4) Locally Weighted Polynomial Regression (LWP). In the suggested simple two-step estimation process, precipitation occurrence is first generated via a logistic regression model before applying IDW scheme (one of the local scheme) to estimate the amount of precipitation separately on wet days. As the results, the suggested method shows the better performance of daily rainfall interpolation which has spatial differences compared with conventional methods. And this technique can be used for streamflow forecasting and downscaling of atmospheric circulation model effectively.

• Journal of the Korean housing association
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• v.16 no.3
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• pp.101-107
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• 2005

The reason that compulsory removals of a low-quality housing redevelopment such as involuntary or unintentional migration present a problem for urban communities is that whether involuntary movers adapt themselves to their new home has an influence on the urban communities that surround them. Moreover, involuntary emigrants have higher probability of choosing faulty residential areas than voluntary emigrants do. This gives rise to a problem of another residential migration for involuntary movers. In order to solve these problems, there is a need for a new housing policy that enables original residents to come back to their old community. However studies for resettlement had not conducted subjects about housing redevelopment characteristics which influences the involuntary movers directly. Instead personal microscopic characteristics such as statistics of resettlement, the moving distance, the reason of moving, improvement of living environment, had been main subjects of farmer studies. So the purpose of this study is to analyze an analysis of the relationship between resettlement and housing redevelopment characteristics. The data used in this study was obtained at 47 areas designated by Seoul (metropolis) since 1990 for redevelopment. Cluster Analysis Is used for dividing high rate of resettlement with low rate of resettlement and Regression Analysis is used for the analysis of the relationship between resettlement and housing redevelopment characteristics. The results of examining the effects of a redeveloped housing complex on returning residents at 47 areas designated by Seoul (metropolis) since 1990 fur redevelopment are as follows: First, A housing complex with a high returning rate (remove-in rate?) has no state/public land, unauthorized building owners who are in the low-income brackets, and few interested parties such as union members. This is the characteristic of a redeveloped housing complex with a short-period project span. On the contrary, a housing complex that has a low returning rate is crowded by state/public land, and numerous unauthorized building owners, and interested parties. Second, According to the linear regression analysis, among the factors that affect returning residents, 'physical properties(characteristics) of a region', 'population properties within a region', and 'properties of a project span' indicate a negative(-)influence whereas 'properties of a complex density' shows a positive(+) influence. In a nutshell, the more the physical properties, population properties, projectspan properties, the lower the returning rate and the more the complex density properties, the higher the returning rate. In detail, an area with many small land and new/large buildings, a high population, and a long project duration has a low returning rate of original residents while an area holding large capacity and buildings with many number of floors (multiple-storied building) has a high returning rate.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.17-30
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• 2002

Incident duration prediction is one of the most important steps of the overall incident management process. An accurate and reliable estimate of the incident duration can be the main difference between an effective incident management operation and an unacceptable one since, without the knowledge of such time durations, traffic impact can not be estimated or calculated. This research presents several multiple linear regression models for incident duration prediction using data consisting of 384 incident cases. The main source of various incident cases was the Traffic Incident Reports filled out by the Motorist Assistant Units of the Korea Highway Corporation. The models were proposed separately according to the time of day(daytime vs. nighttime) and the fatality/injury incurred (fatality/injury vs. property damage only). Two models using an integrated dataset, one with an intercept and the other without it, were also calibrated and proposed for the generality of model application. Some findings are as follows ; ?Variables such as vehicle turnover, load spills, the number of heavy vehicles involved and the number of blocked lanes were found to significantly affect incident duration times. ?Models, however, tend to overestimate the duration times when a dummy variable, load spill, is used. It was simply because several of load spill incidents had excessively long clearance times. The precision was improved when load spills were further categorized into "small spills" and "large spills" based on the size of vehicles involved. ?Variables such as the number of vehicles involved and the number of blocked lanes found not significant when a regression model was calibrated with an intercept. whereas excluding the intercept from the model structure signifies those variables in a statistical sense.

• Nutrition Research and Practice
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• v.10 no.4
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• pp.448-455
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• 2016

BACKGROUND/OBJECTIVES: A growing body of research has indicated that night eating could be associated with poor diet quality and negative health outcomes. This study examined the nutritional aspects of night eating, its related factors, and the association between night eating and body weight among Korean adolescents. SUBJECTS/METHODS: This study analysed the data from a one day 24-hour dietary recall as well as a demographic survey of 1,738 Korean adolescents aged 12 to 18-years-old obtained from the 2010-2012 Korea National Health and Nutrition Examination Survey. 'Night eating' was defined as consuming 25% or more of one's daily energy intake between 21:00 and 06:00. Subjects complying with the preceding condition were classified as 'night eaters', whereas the rest were considered 'non-night eaters'. Logistic regression analysis examined factors related to night eating. Multiple linear regression analyses were used to examine the relationship between night eating and BMI z-scores, whereas multinomial logistic regression analysis was used to examine the relationship between night eating and weight status. RESULTS: About 21% of Korean adolescents appeared to be night eaters. Night eaters showed increased breakfast skipping (P = 0.001), higher energy intake from snacks (P < 0.001), greater proportion of energy intake from fat (P = 0.029), and lower Dietary Diversity Scores (P = 0.008) than non-night eaters. Male adolescents presented 1.9 times higher odds of being night eaters than females. Adolescents whose both parents were night eaters were 4.4 times as likely to be night eaters as those whose neither parents were. Female adolescents showed a significant relationship between night eating and BMI z-scores (${\beta}=0.28$, P = 0.004). However, night eating did not increase odds of being overweight or obese in adolescents. CONCLUSIONS: Night eating in Korean adolescents was related to undesirable dietary behaviours and low diet quality in general as well as higher BMI z-scores in females. Male gender and parental night eating appeared to be the factors that significantly increased odds of night eating. These results suggest that night eating should be considered when designing nutrition education or intervention programs targeting adolescents.

• Journal of Preventive Medicine and Public Health
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• v.42 no.4
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• pp.231-236
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• 2009

Objectives : This study was conducted to determine the appropriate sampling time of the salivary stress markers, chromogranin A (CgA) and cortisol as objective indices of job stress assessment in adult females. Methods : The subjects were 20${\sim}$39-year-old women (13 office workers, 11 sales-service workers, and 11 college students) who were eligible for the study and free of acute and chronic medical conditions. Salivary CgA and cortisol levels were determined by enzyme-linked immunosorbent assay (ELISA). Saliva samples were collected (2 $m{\ell}$ each) at 7:00, 8:00, 10:30, 12:00, 17:30, and 22:30 on a typical day. Salivary CgA and cortisol levels, according to sampling time, were compared among the three groups using general linear model. The full version of the Korean Occupational Stress Scale (KOSS), which includes socioeconomic characteristics, health behavior, workrelated characteristics, and BMI, was used to access the subjects' job stress. Multiple regression analysis of the job stressors identified by the KOSS was performed on salivary CgA and cortisol levels. Results : The salivary CgA level peaked at 7:00 (time of awakening), then decreased and were maintained at a low level throughout the day, and increased slightly at 17:30. The salivary cortisol level increased steeply within the 1st hour after awakening, followed by a gradual decrease by 12:00, and was then maintained at a low level throughout the day. The salivary cortisol levels of subjects who worked ${\leq}$5 days per week and graduated from the university were significantly lower at 8:00 (p=0.006). The salivary cortisol levels of non-smokers were significantly lower at 7:00 p=0.040) and 8:00 (p=0.003) compared to smokers. There were no significant differences in salivary CgA and cortisol levels at 10:30 and 12:00 in general characteristics. The regression coefficients on salivary CgA level were significant with interpersonal conflict at 17:30 and job insecurity at 22:30. Regression coefficients on salivary cortisol level were significant with organizational system and total job stressors at 17:30. Conclusions : We suggest that the appropriate sampling times for the salivary stress markers, CgA and cortisol, are at 7:00 (time of awakening), 8:00 (1 hour after awakening), 17:30 (early evening), and 22:30 (before sleep).

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.

• Tuberculosis and Respiratory Diseases
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• v.72 no.3
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• pp.310-317
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• 2012

Background: Airway obstruction and the extent of emphysema are reported to be responsible for reduced bone mineral density (BMD). Corresponding to different phenotypes of a pulmonary disease, different severity in extra pulmonary features may exist. We compared BMDs of subjects with or without airway obstruction and/or emphysema and investigated the relationships among BMD, the severity of airway obstruction, and the extent of emphysema. Methods: Using a university hospital database, we reviewed patients over 40 years old who performed spirometry, computed tomography of chest, and measurement of BMD of the lumbar (L) spine. According to the presence or absence of airway obstruction and/or emphysema, four groups were classified. Results: Among a total of 59 subjects, 33 (56%) had osteoporosis. The prevalence of osteoporosis in subjects with no airway obstruction and no emphysema, those with only emphysema, those with only airway obstruction, and those with both airway obstruction and emphysema were 42%, 57%, 64%, and 73%, respectively (p=0.047 by linear-by-linear association). The mean T-scores of BMD of L1 (p=0.032) and L1-4 spines were different among the four groups (p=0.034). Although the T-score of L1 BMD negatively correlated with the extent of emphysema (r=-0.275, p=0.035) and positively with each of body mass index (BMI) (r=0.520, p<0.001), forced expiratory volume in one second ($FEV_1$) (r=0.330, p=0.011), $FEV_1$/forced vital capacity (r=0.409, p=0.001), and forced expiratory flow at 25~75% of FVC ($FEF_{25-75%}$) (r=0.438, p=0.0001), respectively, multiple linear regression analysis indicated that BMI (p<0.001) and $FEF_{25-75%}$ were predictive of BMD (p=0.012). Conclusion: Low BMI and airway obstruction were strongly associated with reduced bone density rather than the extent of emphysema.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.131-138
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• 1998

In order to minimize the trial frequency in the new filter cigarette design, we studied the relationship between smoke yield and tipping materials of cigarette. A three levels full factorial design involving filament denier (X1,2.5-3.3d), Porosity of the acetate filter plug wrap (X2, 3,500-16,000CU) and porosity of the tip paper (X3, 400-1,200CU) was used. Three independent factors (Xl, X2, X3) were chosen for their effects on the various responses and the function was expressed in terms of a quadratic polynomial equation, Y : $\beta$o + $\beta$1Xl + $\beta$2X2 + $\beta$3X3 + $\beta$11Xl2 + $\beta$22X22+ $\beta$33X32 + $\beta$12X1X2 + $\beta$13XIX3 $\beta$23X2X3 which measures the linear, quadratic, and interaction effects. Twenty-nine trial numbers were obtained as a results of using a three levels full factorial design and it was analyzed by the multiple regression analysis with backward stepwise in STATISTICA/pc under restricted conditions. Tar yields of the cigarette was affected by porosity of tip paper (0.66), filament denier (0.47) and porosity of plug wrap (0.28) in the decreasing order, and linear effect of tip paper porosity (B3) and filament denier (91) were significant at a level of 0.01($\alpha$). The filament denier and tipping paper porosity interaction F ratio among three factors had a P-value of 0,000041, indicating higher interaction between these factors. Based on the analysis of variance, the model fitted for Tar (Y1) was significant at 5% confidence level and the coefficient of determination (0.96) was the proportion of variability in the data fitted for by the model.

• Journal of Korean Dental Hygiene Science
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• v.7 no.1
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• pp.1-15
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• 2024

Background: This study aims to determine the association between the number of remaining teeth and oral health-related quality of life according to economic activity status in elderly. Methods: Data from the 9th Korean Longitudinal Study of Ageing (KLoSA) were used to analyze 6,004 older adults aged 59 years and older. The number of remaining teeth was categorized as less than 20 and more than 20, and the Geriatric Oral Health Assessment Index (GOHAI) was used to measured the oral health-related quality of life of the elderly. Independent t-tests were performed to compare demographic, economic, sociodemographic, and health characteristics, as well as GOHAI scores, between economically active and inactive individuals. In the case of ANOVA analysis, Scheffe's post hoc analysis was performed to confirm statistical significance between groups. Linear regression analysis was conducted to determine the influence of the number of remaining teeth on GOHAI according to economic activity status. Results: Among the study population, 33.9% were economically active, which is approximately half the proportion of those were not economically active. The mean GOHAI scores were 43.32 and 40.15 for economically active and economically inactive individuals with 20 or more residual teeth, respectively (p<0.001). Simple linear regression analysis revealed that having more than 20 remaining teeth was associated with a statistically significant increase in GOHAI by approximately 4.56 times and 4.92 times compared to having fewer than 20 teeth for economically active and non-economically active individuals, respectively (p<0.001). Multiple linear regression analysis, adjusted for demographic, economic, sociodemographic, and health characteristics, showed that having more than 20 remaining teeth was associated with a statistically significant increase in GOHAI by approximately 3.62 and 2.97 times compared to having fewer than 20 teeth in economically active and non-economically active individuals, respectively (p<0.001). Conclusion: This study explored economic activity status as one of several approaches to enhance the oral health-related quality of life of the elderly. By using the number of remaining teeth as an indicator of oral health status. supporting economic activity could potentially improve both oral health and overall quality of life for older individuals. Such interventions may have positive effects on policy outcomes, including reducing economic inequality by promoting economic engagement among the elderly.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.244-250
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• 2020

The aim of the study is to investigate the effect of the benefit of soft waxing, hard waxing, and sugaring waxing on intention to reuse in Korean adults, and to provide useful information to people who are new to waxing. As a research method, from May 1, 2019 to August 30 (17 weeks), we surveyed 422 subjects between 10 and 40 years old who lived in Busan and Yeongnam area and experienced waxing. In statistical analysis, Cronbach's alpha was calculated for reliability test, and Chi-squared test, independent t-test, correlation analysis and linear regression analysis were used. Multiple responses were analyzed using multiple response test. In the result of the effect of waxing benefit on intention to reuse, there was a significant positive correlation of waxing seeking score by body part, total waxing benefit score(r=0.389, p<0.001), and total score of intention to reuse (r=0.214, p>0.001) with intention to reuse. There was also a significant positive correlation between waxing benefit by body part and intention to reuse, except arms and legs. In the result of the effect of waxing benefit on intention to reuse, face waxing (β=0.106, p<0.001), Brazilian waxing (β=0.221, p<0.001) and total waxing benefit score (β=0.321, p<0.001) had a significant effect on intention to reuse. In the present study, awareness of sugaring waxing was low but favor and intention to reuse were strong, and the subjects sought sugaring waxing for sensitive body parts. Thus, would provide useful information for consumers new to waxing, and also basic information for studies on waxing.