Numerous studies have established a correlation between sociodemographic characteristics and water usage, identifying population as a primary independent variable in mid- to long-term demand forecasting. Recent dramatic sociodemographic changes, including urban concentration-rural depopulation, low birth rates-aging population, and the rise in single-person households, are expected to impact water demand and supply patterns. This underscores the necessity for operational and managerial changes in existing water supply systems. While sociodemographic characteristics are regularly surveyed, the conducted surveys use aggregate units that do not align with the actual system. Consequently, many water demand forecasts have been conducted at the administrative district level without adequately considering the water supply system. This study presents an upward water demand forecasting model that accurately reflects real water facilities and consumers. The model comprises three key steps. Firstly, Statistics Korea’s SGIS (Statistical Geological Information System) data was reorganized at the DMA level. Secondly, DMAs were classified using the SOM (Self-Organizing Map) algorithm to consider differences in water facilities and consumer characteristics. Lastly, water demand forecasting employed the PCR (Principal Component Regression) method to address multicollinearity and overfitting issues. The performance evaluation of this model was conducted for DMAs classified as rural areas due to the insufficient number of DMAs. The estimation results indicate that the correlation coefficients exceeded 0.9, and the MAPE remained within approximately 10% for the test dataset. This method is expected to be useful for reorganization plans, such as the expansion and contraction of existing facilities.

Taking vitamin and mineral supplements is increasingly common with the rapid economic growth. The aim of this study was to determine the prevalence of vitamin and mineral supplement use among adults aged 20 or older from the third Korean National Health and Nutrition Survey data and to explore the effect of sociodemographic and lifestyle factors as well as nutrient intake on taking supplements. People who had participated in both a health questionnaire and a nutritional survey were selected, and 2,871 men and 3,555 women were finally included in this analysis. Both men and women with a higher level of education, those residing in a metropolitan area, and those with higher income were more likely to take supplements. Health behaviors were not significantly associated with taking supplements. Mean nutrient intake of all nutrients except energy intake was not significantly different in men or women taking supplements after adjusting for age, education, marital status, resident area, smoking, and energy intake. Compared to Dietary Reference Intake (DRI) for Koreans, most vitamins and minerals, except vitamin B2 and calcium, were consumed at higher than the Recommended Intake (RI) without supplements. In conclusion, taking supplements such as vitamin B2 and calcium may promote health and prevent disease. However, the type and frequency of other vitamin and mineral supplements consumed should be considered with caution.