• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.6
• /
• pp.699-711
• /
• 2014

This study was carried out to analyze water suspension in the water supply system through fault tree analysis. And quantitative factors was evaluated to minimize water suspension. Consequently the aim of this study is to build optimal planning by analyzing scenarios for water suspension. Accordingly the fault tree model makes it possible to estimate risks for water suspension, current risks is $92.23m^3/day$. The result of scenario analysis by pipe replacement, risks for water suspension was reduced $7.02m^3/day$ when replacing WD4 pipe. As a result of scenario analysis by water district connections, the amount of risk reduction is maximized when it is connecting to network pipe of D Zone. Therefore, connecting to network pipe for D Zone would be optimal to reduce risk for water suspension.

• Journal of Digital Convergence
• /
• v.17 no.8
• /
• pp.249-255
• /
• 2019

Type 2 diabetes mellitus(T2DM) is included in metabolic disorders characterized by hyperglycemia, which causes many complications, and requires long-term treatment resulting in massive medical expenses each year. There have been many studies to solve this problem, but the existing studies have not been accurate by learning and predicting the data at specific time point. Thus, this study proposed a model using RNN to increase the accuracy of prediction of T2DM. This work propose a T2DM prediction model based on Korean Genome and Epidemiology study(Ansan, Anseong Korea). We trained all of the data over time to create prediction model of diabetes. To verify the results of the prediction model, we compared the accuracy with the existing machine learning methods, LR, k-NN, and SVM. Proposed prediction model accuracy was 0.92 and the AUC was 0.92, which were higher than the other. Therefore predicting the onset of T2DM by using the proposed diabetes prediction model in this study, it could lead to healthier lifestyle and hyperglycemic control resulting in lower risk of diabetes by alerted diabetes occurrence.

• Korea journal of population studies
• /
• v.29 no.2
• /
• pp.27-51
• /
• 2006

In this paper, I have tested various kinds of methods for mortality projection and chose Lee-Carter method for projection of Korean mortality by age and sex. I reviewed the trends of life tables and life expectancies by age and sex from 2005 to 2050 projected by Lee-Carter method and found that the method was very applicable for Korean mortality projection. The differences between reported and estimated data for the period of 1971-2003 were small enough for both sexes and for all of the age groups. The projected life expectancies in 2051 were 82.73 years for males and 89.41 for females, and the differences decreased from 7.06 years in 2005 to 6.68 years. Because of the limitation of Korean infant mortality rate, I adopted the Japanese estimated IMR in 2050 as Korean object level in 2051. When the time series of IMR become long enough, we can use Korean IMR directly for the mortality projection. In addition, if we can estimate the changes of the main cause of death correctly in future, the mortality projection will be more correct and reliable. This will be available when we can produce a long series of life tables by cause of deaths.

• KIPS Transactions on Software and Data Engineering
• /
• v.9 no.4
• /
• pp.137-144
• /
• 2020

Delirium is among the most common mental disorders encountered in patients with a temporary cognitive impairment such as consciousness disorder, attention disorder, and poor speech, particularly among those who are older. Delirium is distressing for patients and families, can interfere with the management of symptoms such as pain, and is associated with increased elderly mortality. The purpose of this paper is to generate useful clinical knowledge that can be used to distinguish the outcomes of patients with delirium in long-term care facilities. For this purpose, we extracted the clinical classification knowledge associated with delirium using a local covering rule acquisition approach with the rough lower approximation region. The clinical applicability of the proposed method was verified using data collected from a prospective cohort study. From the results of this study, we found six useful clinical pieces of evidence that the duration of delirium could more than 12 days. Also, we confirmed eight factors such as BMI, Charlson Comorbidity Index, hospitalization path, nutrition deficiency, infection, sleep disturbance, bed scores, and diaper use are important in distinguishing the outcomes of delirium patients. The classification performance of the proposed method was verified by comparison with three benchmarking models, ANN, SVM with RBF kernel, and Random Forest, using a statistical five-fold cross-validation method. The proposed method showed an improved average performance of 0.6% and 2.7% in both accuracy and AUC criteria when compared with the SVM model with the highest classification performance of the three models respectively.

• 한국노년학
• /
• v.41 no.3
• /
• pp.397-420
• /
• 2021

The paper tried to determine relationships between volunteering and hypertension risks, symptom betterment, activity difficulty occurrences, and medicine treatment among middle-aged and older adults, with a prospective cohort study. Multilevel mixed-effects generalized linear models were used for the analysis of longitudinal panel data collected over 10 years from 2008 to 2018, using 5,867 cohort samples. The results showed that those who volunteered at least 200 hours per year were 3.4 times more lower than not-volunteering in risks of hypertension, those who volunteered yearly 50~99 hours were a lot more improved than not-volunteering in the symptom betterment, those who volunteered yearly at least 200 hours were 7.7 times lower than not-volunteering in activity difficulty occurrences, and those who volunteered yearly 50~99 hours were 2.5 times lower than not-volunteering in the occurrences of medicine treatment. These indicate that volunteering among middle-aged and older adults may have health benefits against incident hypertension. Finally the thesis discusses the study limitations, future directions of studies, and the practices implications.

• Korean Journal of Social Welfare
• /
• v.52
• /
• pp.33-61
• /
• 2003

This study aims to identify early retirement and the subsequent career ending patterns and explain the phenomena in terms of social security policies and labor market perspectives. Although many older workers retire early, there are very few studies to examine how the retirees end their careers after quitting the long-time jobs. The paper investigates individual work experiences 55 through 61, identifies the career ending patterns, constitutes the micro and macro analytical models to estimate the impacts of labor market and work-related variables. The findings show that many older workers have diverse career ending patterns after long-time career jobs, that is, still working at age-55 job, exiting and reentering, sporadic work, retired permanently from age-55 job, a repeat of labor force entry. Also the estimation results indicate that pension, social security, labor market condition, work structure variables better explain the career ending behaviors than social psychological factors of health, education, attitudes toward retirement and job, ethnicity. Finally, this paper discusses theoretical importances of labor market perspectives and policy implications at the end of thesis.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.11
• /
• pp.94-103
• /
• 2016

This study was conducted to investigate the association of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) with all-cause mortality among populations. The data used were from a Korean Genome and Epidemiology Study (KoGES) based on health examinations and questionnaires. The subjects consisted of 10,110 persons aged 40 and over. Hazard ratio was analyzed using Cox's proportional hazard model. The hazard ratio of AST (${\geq}50.0\;IU/L$) was 2.198 (95% CI: 1.217-3.971) after being adjusted for age, sex, education, regular exercise, smoking, drinking, WHR, and TG. In conclusion, AST was an independent significant risk factor of all-cause mortality, and ALT showed a tendency to increase. Overall, these findings indicate that AST and ALT may be useful tools for predicting mortality.

• Korea journal of population studies
• /
• v.24 no.1
• /
• pp.67-90
• /
• 2001

Korea National Statistical Office(KNSO) estimated period birth rates, period death rates, and probability of dying for infant(q$q_{0}$) at period life table, considering the unregistered infant deaths. As Ministry of Health and Welfare(MHW) conducted 1993 and 1996 birth cohort infant death surveys. KNSO re-estimated infant mortality levels(especially q$q_{0}$). For the re-estimation, reference data were derived from death registration. MHW surveys, death registration of developed countries. Model Life Tables, and Life Table for Japan. Seventeen simulations were made by the combination of estimation methods and reference data. The final $q_{0}$ was estimated based on the relationship between $q_{0}$ of MHW 1993 survey and $q_{1-4}$ of registered deaths for the period of 1971~1997. For 1993, $q_{0}$ was calculated directly from the 1993 MHW survey and interpolation and extrapolation were made for 1995 and 1997 using the relative decrease rates of $q_{0}$ between 1993 and 1996 MHW surveys. Utilizing the formular of Coale-Demeny North Model, $q_{0}$ was transformed into $m_{0}$ for the period 1971~1997. Finally, cremation data are found to be very useful for the estimation of 1998 infant mortality level by supplementing unregistered infant deaths, especially neonatal deaths. Furthermore, they are found to be very useful to produce fetal and perinatal death statistics.

• Journal of Nutrition and Health
• /
• v.52 no.6
• /
• pp.552-558
• /
• 2019

Purpose: Although vitamin D deficiency is common among Korean adolescent girls and young women, few studies have explored the potential health effects of vitamin D deficiency in this vulnerable population. This study examined the association between vitamin D deficiency and anemia in Korean adolescent girls and young women. Methods: The data from the Korea National Health and Nutrition Examination Survey 2008 ~ 2014 were used. A total of 3,643 girls and adult women aged 12 to 29 who provided all the information (including serum 25-hydroxy vitamin D, hemoglobin, and/or serum ferritin) needed for the analysis were included in the analysis. Demographic, lifestyle, and health data were obtained through survey questionnaires. Anemia and iron deficiency anemia were defined according to the World Health Organization cut-offs. Multivariable logistic regression, and restricted cubic spline regression were used in the analysis. Results: In fully adjusted logistic regression models, the vitamin D deficiency was significantly associated with higher prevalences of anemia (odds ratio (OR): 1.61, 95% confidence interval (CI): 1.04 ~ 2.49) and iron deficiency anemia (OR: 1.43, 95% CI: 1.01 ~ 2.03). In a cubic spline regression model, we observed a dose-response relationship between serum 25(OH)D concentration and anemia, and this linear relationship was also clearly observed between serum 25(OH)D concentration and iron deficiency anemia. Conclusion: Vitamin D deficiency may be associated with a higher prevalence of iron deficiency anemia and anemia in adolescent girls and young women. Alternatively, vitamin D deficiency may be a concurrent event for patients with anemia, which we cannot distinguish in this cross-sectional study. Further studies are needed to verify the causality in this population of low vitamin D levels.

• Journal of Nutrition and Health
• /
• v.47 no.2
• /
• pp.113-123
• /
• 2014

Purpose: Vitamin D has been known to play an important role in the central nervous system and brain functions in the human body, and cumulative evidence has shown that vitamin D deficiency might be linked with various mental health conditions. Epidemiologic studies have shown that vitamin D deficiency may be associated with higher risk of depression in the US and European populations. However, limited information is available regarding the association between vitamin D status and depression in the Korean population. The objective of this study was to examine the associations between vitamin D levels and prevalence of depression. Methods: We conducted a cross-sectional analysis using nationally representative data from the 2008-2010 Korean National Health and Nutrition Examination Survey from which serum 25-hydroxyvitamin D concentrations were available. A total of 18,735 adults who had available demographic, dietary, and lifestyle information were included in our analysis. We defined "depression" with a diagnosis by a physician. "Depressed condition" was defined as having feelings of sadness or depression without diagnosis by a physician. Results: The prevalence of depression was 1.63% and 5.43% in Korean men and women, respectively; 12.5% of men and 26.1% of women were defined as the group having depressed conditions. In multivariate logistic regression models, no significant associations were observed between vitamin D status and prevalence of depression or depressed conditions in Korean men and women. Conclusion: We found no association between vitamin D insufficiency and depression/depressed conditions in Korean adults. Future large prospective studies and randomized controlled trials are needed to confirm this relationship.