• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.19-26
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• 2017

Concrete is a construction material with porous media and corroded steel inside affects negatively to durability and structural safety. This study aims a derivation of quantitative relationship between measured HCP (Half Cell Potential) and corrosion amount considering cover depth and W/C (water to cement) ratio. For the work, cement mortar specimens with 3 different W/C ratios and 4 different cover depths are prepared, HCPs are measured with 3 different corrosion level. HCP measurement significantly increases in the saturated condition and linear relationship is observed between corrosion level and acceleration period. With increasing corrosion level and W/C ratio, and decreasing cover depth, HCP measurement increases. Considering total corrosion level and HCP measurements, relatively low COV(Coefficient of Variation) of 0.67 is evaluated through multi-linear regression analysis, however higher COVs over 0.90 can be obtained considering level of HCP measurement. In the room condition, corrosion level can be evaluated through measured HCP in the given conditions of cover depth, W/C ratio. diameter of steel inside.

• Journal of Preventive Medicine and Public Health
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• v.46 no.5
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• pp.271-281
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• 2013

Objectives: Emerging evidence indicates that sleep duration is associated with health outcomes. However, the relationship of sleep duration with long-term health is unclear. This study was designed to determine the relationship of sleep duration with mortality as a parameter for long-term health in a large prospective cohort study in Korea. Methods: The study population included 13 164 participants aged over 20 years from the Korean Multi-center Cancer Cohort study. Information on sleep duration was obtained through a structured questionnaire interview. The hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality were estimated using a Cox regression model. The non-linear relationship between sleep duration and mortality was examined non-parametrically using restricted cubic splines. Results: The HRs for all-cause mortality showed a U-shape, with the lowest point at sleep duration of 7 to 8 hours. There was an increased risk of death among persons with sleep duration of ${\leq}5$ hours (HR, 1.21; 95% CI, 1.03 to 1.41) and of ${\geq}10$ hours (HR, 1.36; 95% CI, 1.07 to 1.72). In stratified analysis, this relationship of HR was seen in women and in participants aged ${\geq}60$ years. Risk of cardiovascular disease-specific mortality was associated with a sleep duration of ${\leq}5$ hours (HR, 1.40; 95% CI, 1.02 to 1.93). Risk of death from respiratory disease was associated with sleep duration at both extremes (${\leq}5$ and ${\geq}10$ hours). Conclusions: Sleep durations of 7 to 8 hours may be recommended to the public for a general healthy lifestyle in Korea.

• Journal of Technologic Dentistry
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• v.32 no.1
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• pp.25-34
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• 2010

This study was the study verifying dental technicians' motivation and job satisfaction in Seoul through the positive method as well as its purposes were to investigated the effect of dental technicians manpower supply/demand prospect on motivation, job satisfaction and the effect of other job satisfaction factors on dental technicians motivation and job satisfaction. For then, general characteristics of study objects were classified by sex, married/unmarried, age, career, salary, highest level of education, working place, position and job as well as job satisfaction factors were classified with future supply/demand prospect, future prospect, working hours, working environment and salary. We conducted a frequency analysis, crossing analysis and multi-linear regression analysis about the effect of the classified articles on motivation and job satisfaction. Also, for verifying the relationship of motivation and job satisfaction, we conducted correlation analysis and its result is as followed. First, it showed that the job related with making orthodontic appliance influenced on motivation, among the age, career and job of the general characteristics, and other jobs between working place and job influenced on job satisfaction. Second, the dark future prospect was showed to influence on motivation and job satisfaction highly so we could grasp that negative opinions are included in that. And low-paying was showed to highly influence on job satisfaction s fall so we could grasp the subjective low-salary standard at the present. But we expected that the manpower supply/demand prospect would influence on motivation and job satisfaction but there was little influence. Third, the correlation between motivation and job satisfaction was showed to be somewhat high, motivation had the standard which is above average and job satisfaction had the standard which is below the average. So with a little improving of job satisfaction, it s possible that motivation can be very high. Therefore, in rapidly changing generation, we think that the dental technicians are actively coping with the reality of low-paying and high-working. But it's implying that anxiety for uncertain future was reflected. Furthermore, because institutional strategies for dental technicians' efficient management are insufficient in relation with policies so it's necessary the policy consideration for solve the job-unsatisfying factors actively.

• Economic and Environmental Geology
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• v.48 no.2
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• pp.147-160
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• 2015

In 2014, on 31 August and 1 September, the emissions of $CH_4$, $CO_2$, and $O_2$ gases were measured six times using the closed chamber method from exposed tidal flat sediments in the same position relative to the low point of the tidal cycle in the Eoeun-ri, Taean-gun, on the Mid-western Coast of Korea. The concentrations of $CH_4$ in the air sample collected in the chamber were measured using gas chromatography with an EG analyzer, model GS-23, within 6 hours of collection, and the other gases were measured in real time using a multi-gas monitor. The gas emission fluxes (source (+), and sink (-)) were calculated from a simple linear regression analysis of the changes in the concentrations over time. In order to see the surrounding parameters (water content, temperature, total organic carbon, average mean size of sediments, and the temperature of the inner chamber) were measured at the study site. On the first day, across three measurements during 5 hours 20 minutes, the observed $CO_2$ flux absorption was -137.00 to $-81.73mg/m^2/hr$, and the $O_2$ absorption, measured simultaneously, was -0.03 to $0.00mg/m^2/hr$. On the second day using an identical number of measurements, the $CO_2$ absorption was -20.43 to $-2.11mg/m^2/hr$, and the $O_2$ absorption -0.18 to $-0.14mg/m^2/hr$. The $CH_4$ absorption before low tide was $-0.02mg/m^2/hr$ (first day, Pearson correlation coefficient using the SPSS statistical analysis is -0.555(n=5, p=0.332, pronounced negative linear relationship)), and $-0.15mg/m^2/hr$ (second day, -0.915(n=5, p=0.030, strong negative linear relationship)) on both measurement days. The emitted flux after low tide on both measurement days reached a minimum of $+0.00mg/m^2/hr$ (+0.713(n=5, p=0.176, linear relationship which can be almost ignored)), and a maximum of $+0.03mg/m^2/hr$ (+0.194(n=5, p=0.754, weak positive linear relationship)) after low tide. However, the absolute values of the $CH_4$ fluxes were analyzed at different times. These results suggest that rate for $CH_4$ fluxes, even the same time and area, were influenced by changes in the tidal cycle characteristics of surface sediments for understanding their correlation with these gas emissions, and surrounding parameters such as physiochemical sediments conditions.

• Journal of Industrial Convergence
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• v.21 no.5
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• pp.51-58
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• 2023

The purpose of this study is to analyze suicidal ideation of elderly people with diabetes living alone and to investigate the relationship between suicidal ideation, loneliness, and depression. This study was conducted through secondary data analysis using total survey data for the elderly living alone in O province. The subjects of this study were 466 elderly people who were diagnosed with diabetes among the elderly living alone. The data of this study were analyzed using descriptive statistics, t-test, Pearson's correlation coefficients, multi-linear regression analysis, and the three-step mediating effect verification procedure of Baron & Kenny using the SPSS 26.0 program. The average loneliness score and average depression score of the subjects were 4.52±3.30 and 4.88±4.03, respectively, and 27.3% of the subjects said they had a suicidal ideation. The subject's loneliness (β=.20, p=.005) and depression (β=.30, p<.001) was found to be a significant factor in predicting suicide ideation. In addition, depression was found to be partially mediated in the relationship between loneliness and suicidal ideation. Through the results of this study, loneliness and depression were found to be important factors related to suicidal ideation in the elderly with diabetes living alone. In addition, in order to improve suicidal ideation in the elderly with diabetes living alone, intervention to lower the level of loneliness and depression is necessary.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.5
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• pp.779-784
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• 2013

This study aims to look into the relationship between the parents's family history of diabetes and factors of metabolic syndrome focusing on Korean adult males with a family history of diabetes. The data used for the study was collected from the 2010 Korea National Health and Nutrition Examination Survey. The subjects of the study totaled 2,045. For statistical analysis, double sampling general linear regression was used and the statistical significance was p<0.05. As a result of a multi-variate analysis with general characteristics corrected, the following was discovered: when fathers had a family history of diabetes, girth increased by 2.5cm, fasting blood sugar(glu) increased by 9.6mg/dL and neutral fat increased by 41.6mg/dL When the mothers had a family history of diabetes, girth increased by 2.4cm, fasting blood sugar(glu) increased by 15.4mg/dL, and the neutral fat increased by 27.2mg/dL. In conclusion, when the fathers had a family history of diabetes, their children's girth, fasting blood sugar and neutral fat were significantly higher, and when the mothers had a family history of diabetes, their children's girth and fasting blood sugar were significantly higher.

• Health Policy and Management
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• v.33 no.3
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• pp.311-324
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• 2023

Background: Long-term care insurance for the elderly has been stably established along with the quantitative expansion of long-term care facilities. Indeed, the need for a paradigm about human rights-based service approach is being raised throughout society from a service perspective. Therefore, this study aimed to analyze the association between elderly human rights awareness and quality of service by considering human rights education as a moderate variable. Methods: This study conducted surveys with 138 caregivers working in long-term care facilities located in Seoul and Gangwon. General characteristics, awareness of human rights, and the level of service quality were examined using descriptive statistics, frequency analysis, and correlation analysis. And multi-variable linear regression with a hierarchical framework was employed. These analyses were performed using IBM SPSS ver. 25.0. Results: Of the 138 caregivers, 97.1% were female, 87.7% were more than 50 years old, and most of their education level was high-school graduates. Their length of employment ranged from more than 5 years to less than 10 years. The level of awareness regarding elderly human rights of the elderly was below normal (mean=2.21), but the quality of service was high (mean=4.21), and the need for human rights education was also high (mean=4.28). Among the general characteristics, the length of employment was significantly associated with awareness of elderly human rights. Moreover, political rights awareness, included as sub-domains of human rights, was positively associated with quality of service. However, the moderating variable, human rights education, was not significantly associated with the quality of service. Conclusion: In this study, human rights education, as a moderating variable, did not have a statistically significant effect on caregivers' human rights awareness in relation to service quality. This finding is inconsistent with previous research results. These results can be explained by the fact that the frequency of education in long-term care facilities was a significant factor in the practice of protecting the human rights of the elderly. Therefore ongoing encouragement for the frequency of current human rights education and improvements in the educational approach appear to be necessary. In addition, these findings reveal the need for strength of education policies and effective in-depth research about human rights and quality of service to respect the human rights of the elderly.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.329-339
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• 2021

Soybeans (Glycine max), one of major upland crops, require precise management of environmental conditions, such as temperature, water, and soil, during cultivation since they are sensitive to environmental changes. Application of spectral technologies that measure the physiological state of crops remotely has great potential for improving quality and productivity of the soybean by estimating yields, physiological stresses, and diseases. In this study, we developed and validated a soybean growth prediction model using multispectral imagery. We conducted a linear regression analysis between vegetation indices and soybean growth data (fresh weight and LAI) obtained at Miryang fields. The linear regression model was validated at Goesan fields. It was found that the model based on green ratio vegetation index (GRVI) had the greatest performance in prediction of fresh weight at the calibration stage (R²=0.74, RMSE=246 g/m², RE=34.2%). In the validation stage, RMSE and RE of the model were 392 g/m² and 32%, respectively. The errors of the model differed by cropping system, For example, RMSE and RE of model in single crop fields were 315 g/m² and 26%, respectively. On the other hand, the model had greater values of RMSE (381 g/m²) and RE (31%) in double crop fields. As a result of developing models for predicting a fresh weight into two years (2018+2020) with similar accumulated temperature (AT) in three years and a single year (2019) that was different from that AT, the prediction performance of a single year model was better than a two years model. Consequently, compared with those models divided by AT and a three years model, RMSE of a single crop fields were improved by about 29.1%. However, those of double crop fields decreased by about 19.6%. When environmental factors are used along with, spectral data, the reliability of soybean growth prediction can be achieved various environmental conditions.

• 한국사회복지학회:학술대회논문집
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• 2003.10a
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• pp.185-216
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• 2003

This study was aimed at investigating important factors influencing career success among regular workers. The current researcher scrutinized the degree to which variables and factors affect the career success and occupational turnover rates of the research participants. At the same tune, two hypothetical path models established by the researcher were examined using linear multiple regression methods and the LISREL. After examining the differences among the factors of career success, a comparison was made between the disabled worker group and the non-disabled worker group. A questionnaire using the 5-point Likert scale was distributed to a group of 374 workers with disabilities and 463 workers without disabilities. For the data analysis purpose, the structural equation model, factor analysis, correlation analysis, and multiple regression analysis were carried out. The results of this study ran be summarized as follows. First, the results of factor analysis showed important categories of conceptual themes of career success. The initial conceptual factor model did not accord with the empirical one. A three-factorial model revealed categories of personal, family, and organizational factor respectively. The personal factor was composed of the self-esteem and self-efficiency. The family factor was consisted of the multi-roles stress and the number of children. Finally, the organizational factor was composed of the capacity for utilizing resources, networking, and the frequency of mentoring. In addition, the total 10 sub areas of career success were divided by two important aspects; the subjective career success and the objective career success. Second, both research participant groups seemed to be influenced by their occupational types. However, all predictive variables excluding the wage rate and the average length of work years had significant impact on job success for the disabled work group, while all the variables excluding the frequency of advice and length of working years had significant impact on job success for the non-disabled worker group. Third, the turnover rate was significantly influenced by the age and the experience of turnover of the research participants. However, the number of co-workers was the strongest predictive variable for the worker group with disabilities, but the occupation choice variable for the worker group without disabilities. For the disabled worker group, the turnover rate was differently influenced by the type of occupation, the length of working years, while multi-role stress and the average working years at the time of turnover for the worker group without disabilities. Fifth, as a result of verifying the hypothetical path model, it showed that the first model was somewhat proper and could predict the career success on both research participant groups. In the second model, the Chi-square, the degree of freedom (($x^2=64.950$, df=61, P=0.341), and the adjusted Goodness of Fit Index (AGFI) were .964, and the Comparative Fit Index (CFI) were .997, and the Root Mean Squared Residual (RMR) was respectively. .038. The model was best fitted and could predict the career success more highly because the goodness of fit index in the whole models was within the allowed range. In conclusion, the following research implications can be suggested. First, the occupational type of research participants was one of the most important variables to predict the career success for both research participant groups. It means that people with disabilities require human development services including education. They need to improve themselves in this knowledge-based society. Furthermore, for maintaining the career success, people with disabilities should be approached by considering the subjective career success aspects including wages and the promotion opportunities than the objective career success aspects.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.2
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• pp.234-252
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• 2010

This paper examines the tendency of housing assets to become increasingly quasi-financial assets by analyzing the relationships between risks and returns in three Gangnam districts (Gangnam-gu, Seocho-gu and Songpa-gu) apartment markets in Seoul, especially for the apartments to be reconstructed, capitalizing upon some capital asset pricing models (CAPM). A single factor CAPM model shows positive relationships between risks and returns regardless of the types of apartments in three Gangnam districts. Multi-factors CAPM models also confirm that the market and SMB (small minus big) factors are positively related to the rate of returns regardless of the types of apartments. However, the unsystematic risk factor is found to be statistically positive especially for the apartments to be reconstructed, while the momentum factor is dependent upon the regression models used. An analysis on some portfolios classified by the size of apartments and price volatility and/or beta values suggests that there are the positive linear relationships between risks and returns and the SMB factor is clearly found to be significant in determining the rate of returns. In particular, housing assets are highly highlighted as investment goods and/or quasi financial assets for the apartments to be constructed in the Gangnam housing.