• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.417-424
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• 2021

Algal bloom is an ongoing issue in the management of freshwater systems for drinking water supply, and the chlorophyll-a concentration is commonly used to represent the status of algal bloom. Thus, the prediction of chlorophyll-a concentration is essential for the proper management of water quality. However, the chlorophyll-a concentration is affected by various water quality and environmental factors, so the prediction of its concentration is not an easy task. In recent years, many advanced machine learning algorithms have increasingly been used for the development of surrogate models to prediction the chlorophyll-a concentration in freshwater systems such as rivers or reservoirs. This study used a light gradient boosting machine(LightGBM), a gradient boosting decision tree algorithm, to develop an ensemble machine learning model to predict chlorophyll-a concentration. The field water quality data observed at Daecheong Lake, obtained from the real-time water information system in Korea, were used for the development of the model. The data include temperature, pH, electric conductivity, dissolved oxygen, total organic carbon, total nitrogen, total phosphorus, and chlorophyll-a. First, a LightGBM model was developed to predict the chlorophyll-a concentration by using the other seven items as independent input variables. Second, the time-lagged values of all the input variables were added as input variables to understand the effect of time lag of input variables on model performance. The time lag (i) ranges from 1 to 50 days. The model performance was evaluated using three indices, root mean squared error-observation standard deviation ration (RSR), Nash-Sutcliffe coefficient of efficiency (NSE) and mean absolute error (MAE). The model showed the best performance by adding a dataset with a one-day time lag (i=1) where RSR, NSE, and MAE were 0.359, 0.871 and 1.510, respectively. The improvement of model performance was observed when a dataset with a time lag up of about 15 days (i=15) was added.

• 한국노년학
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• v.30 no.1
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• pp.241-260
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• 2010

This study aims to fully understand the experience of elderly men living alone in a single room occupancy(Chokbang) by identifying the meaning and essence of their experiences. This research used purposive sampling. The data were collected for 7 months from september 2008 to march 2009. Eight elderly men participated in the interview. Mainly the semi-structured in-depth interview and focus group interview were used. The data analysis was based on Giorgi's 4 types of specific steps. As a result, 4 components and 16 subordinate components were drawn from the analysis. The components resulted from the analysis are: , , , . Based on these results, I discussed the attitudes of the elderly men living alone in Chokbang in meaningful and gender-sensitive ways. Moreover, I provided social welfare connotation and future research suggestions.

• Research in Community and Public Health Nursing
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• v.32 no.4
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• pp.430-444
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• 2021

Purpose: This study is an integrated literature review to analyze health problems and social determinants of multicultural adolescents in South Korea. Methods: An integrative review was conducted according to Whittemore & Knafl's guideline. An electronic search that included publications from 2018 to 2020 in the PubMed, EMBASE, Cochrane Library, CINAHL, RISS, and KISS databases was conducted. Of a total of 67 records that were identified, 13 finally met full inclusion criteria. Text network analysis was also conducted to identify keywords network trends using NetMiner program. Results: The health problems of multicultural adolescents were classified into mental health (depression, anxiety, suicide and acculturative stress) and health risk behaviors (smoking, risky drinking, smartphone dependence and sexual behavior). As social determinants affecting the health of multicultural adolescents, the biological factors such as gender, age, and visible minority, and the psychological factors such as acculturative stress, self-esteem, family support, and ego-resiliency were identified. The sociocultural factors were identified as family economic status, residential area, parental education level, and parents' country of birth. As a result of text network analysis, a total of 41 words were identified. Conclusion: Based on these results, mental health and health risk behaviors should be considered as interventions for health promotion of multicultural adolescents. Our findings suggest that further research should be conducted to broaden the scope of health determinants to account for the effects of the physical environment and health care system.

• Korean Journal of Community Nutrition
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• v.27 no.5
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• pp.406-421
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• 2022

Objectives: The purpose of this study was to investigate the blood biochemical characteristics, comorbidities, dietary intake, and other risk factors leading to poor glycated hemoglobin (HbA1c) control in elderly Korean diabetes patients over 65 years of age. Methods: Data from the 4^th (2007-2009) and the 7^th (2016-2018) Korea National Health and Nutrition Examination Surveys (KNHANES) were used. Socio-demographic characteristics (age, gender, region, household income, education level, marital status, nutrition education, diabetes duration and diabetes treatment), lifestyle characteristics (drinking, smoking, regular walking, and subjective health perception), anthropometric characteristics (height, weight, and waist circumference), blood biochemical characteristics (HbA1c, high- density lipoprotein cholesterol, triglycerides, total cholesterol, blood urea nitrogen, and blood creatinine), co-morbidities (obesity, hypertension, hypercholesterolemia, hypertriglyceridemia, and anemia), energy and nutrients intake, food group intake, and HbA1c control-related risk factors were compared. Results: Compared to the 4^th survey, the 7^th survey showed an increase in diabetes prevalence among men, an increase in the prevalence of diabetes in the older patients, and an increase in the duration of diabetes. The energy ratio from carbohydrate consumption in the 7^th survey was lower than in the 4^th. Compared to the 4^th survey, thiamine and riboflavin intake had improved, and the intakes of vitamin A, vitamin C, and niacin had worsened in the 7^th. A comparison of food group intakes showed that there was a decrease in the consumption of whole grains, potatoes, and milk and an increase in the intake of beverages and alcoholic beverages. The risk factors for poor control of HbA1c were the duration of diabetes and co-morbid hypertriglyceridemia in the 4^th survey, whereas subjective health perception, obesity, and hypercholesterolemia as co-morbidities were found to be risk factors in the 7^th in addition to the risk factors highlighted in the 4^th survey. Conclusions: For the future management of elderly Korean diabetes patients, greater care is indicated for men over 75 years, and those with low levels of education. It is necessary to increase the intake of milk and vegetables, and reduce the intake of beverages and alcoholic beverages. In addition, it is necessary to reduce the incidence of obesity, hypercholesterolemia, and hypertriglyceridemia for proper control of blood sugar.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.45-51
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• 2022

Whether Dokdo can sustain human habitation or economic life of their own plays an important role to the legal status of the island in the international maritime law. This study reports the hydrological survey results regarding the water resource of the island occurred at Moolgol in Seodo. The amount of underground discharge at Moolgol was estimated at least 1.1 m³/d, conforming the results of previous studies. Based on the oxygen and hydrogen isotope ratios of water, the discharge appeared to originate from precipitation, and about 36% of the daily precipitation moves fast to the Moolgol through the joints developed in the volcanic bedrocks. Quality of the discharged water shows relatively higher concentrations in Cl and NO₃ to be used for drinking and domestic purposes, probably affected by the sea spray and waves from surrounding sea and the birds' excretion such as black-tailed gulls.

• Journal of The Korean Society of Clinical Toxicology
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• v.20 no.2
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• pp.58-65
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• 2022

Purpose: Alcohol is one of the most commonly co-ingested agents in deliberate self-poisoning (DSP) cases presenting at the emergency department (ED). The increased impulsivity, aggressiveness, and disinhibition caused by alcohol ingestion may have different clinical features and outcomes in cases of DSP. This study investigates whether alcohol co-ingestion affects the clinical features and outcomes of DSP patients in the ED. Methods: This was a single-center retrospective study. We investigated DSP cases who visited our ED from January 2010 to December 2016. Patients were classified into two groups: with (ALC+) or without (ALC-) alcohol co-ingestion. The clinical features of DSP were compared by considering the co-ingestion of alcohol, and the factors related to discharge against medical advice (AMA) of DSP were analyzed. Results: A total of 689 patients were included in the study, with 272 (39.5%) in the ALC+ group. Majority of the ALC+ group patients were middle-aged males (45-54 years old) and arrived at the ED at night. The rate of discharge AMA from ED was significantly higher in the ALC+ group (130; 47.8%) compared to the ALC- group (p=0.001). No significant differences were obtained in the poisoning severity scores between the two groups (p=0.223). Multivariate analysis revealed that alcohol co-ingestion (odds ratio [OR]=1.42; 95% confidence interval [CI], 1.01-1.98), alert mental status (OR=1.65; 95% CI, 1.17-2.32), past psychiatric history (OR=0.04; 95% CI, 0.01-0.28), age >65 years (OR=0.42; 95% CI, 0.23-0.78), and time from event to ED arrival >6 hrs (OR=0.57; 95% CI, 0.37-0.88) were independent predictive factors of discharge AMA (p=0.043, p=0.004, p=0.001, p=0.006, and p=0.010, respectively). Conclusion: Our results determined a high association between alcohol co-ingestion and the outcome of discharge AMA in DSP patients. Emergency physicians should, therefore, be aware that DSP patients who have co-ingested alcohol may be uncooperative and at high risk of discharge AMA.

• Journal of the Korean Society of Food Culture
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• v.25 no.1
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• pp.17-24
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• 2010

The purpose of this study was to investigate nutritional knowledge, practice of eating behavior guidelines, and problematic dietary habits in working high school students in comparison with non-working high school students. A survey questionnaire was formulated to obtain information on demographic variables, body size, part-time jobs, nutritional knowledge, practice of eating behavior guidelines, and dietary habits. The developed questionnaire was given out to 515 students attending a vocational high school in Yongin, Gyeonggi-Do. Those who had been working 5 hours or more per day for at least a month at the time of survey administration were defined as working students for this study. Proportions of working students were similar between male and female students (i.e. 49.5% for male, 50.5% for female). No significant difference was found in scores of nutritional knowledge between working ($8.43{\pm}2.29$) and non-working students ($8.60{\pm}2.19$). However, some dietary habits were found to be dependent on working status. While approximately 43% of non-working students reported skipping a meal, about 57% of working students did so (p<0.01). The proportion of students with any drinking experience was significantly higher among working students (92%) compared to non-working students (80%) (p<0.001). Working students were found to drink alcoholic beverages more often than non-working students (p<0.001). The mean score of practice of eating behavior guidelines was lower in working students than non-working students. The magnitude of this difference was modest ($51.33{\pm}0.63$ in working students, $53.40{\pm}0.51$ in non-working students), but reached statistical significance (p<0.01). Based on the findings from this study, it is suggested that specific behavior-oriented messages to improve certain problematic dietary habits need to be directed toward working high school students.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.48.1-48.13
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• 2023

Background: This study was conducted to identify the success rate for smoking cessation over time after participation in a therapeutic smoking cessation camp, and to identify how participant characteristics, including a supportive workplace environment for smoking cessation (SWESC), affect the success rate for smoking cessation. Methods: In all, 296 participants at smoking cessation camps in Ulsan between 2015 and 2020 were investigated. The success rates of smoking cessation after weeks 4, 6, 12, and 24 at camp were investigated. The participants were grouped as workers with an SWESC, and workers without an SWESC, and variables (age, education, household income, marital status, drinking, exercise, body mass index, morbidity, job, number of counseling sessions, cigarettes smoked per day and smoking initiation age) were investigated. Multiple logistic regression analysis was conducted at each time point. In addition, Cox regression analysis was performed to evaluate the variables affecting the success rate for smoking cessation over time. Results: The smoking cessation success rate of workers with an SWESC at week 24 (90.7%) was higher than that for workers without an SWESC (60.5%). Multiple logistic regression was performed to determine the relationship between each variable and the success rates for smoking cessation at week 6, 12, and 24. SWESC was confirmed as significant (p < 0.05) variables for increased success rate for smoking cessation at all 3 time points. After adjusting for all variables, the Cox proportional hazards survival analysis showed a hazard ratio of 6.17 for SWESC (p < 0.001,; 95% confidence interval: 3.08-12.38). Conclusions: At a professional treatment smoking cessation camp, participants with an SWESC showed a significantly higher success rate for smoking cessation. Supportive workplace environment for workers' health is expected to be an important factor for smoking cessation projects as well as other health promotion projects at workplace.

• Journal of Industrial Convergence
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• v.22 no.7
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• pp.81-91
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• 2024

This study was conducted to determine the status of allergic diseases and mental health in adolescents, confirm the relationship between allergic diseases and mental health, and provide basic data for developing effective disease management measures for adolescents at the developmental stage. Secondary analysis was performed on the data from the 17^th Youth Health Behavior Online Survey, and complex sample descriptive statistics, cross-tabulation, and logistic regression analysis were performed using the SPSS 26.0 program. As a result of the study, those with one or more allergic diseases were 1.286 times more likely to have stress (B=1.286, p<.000), 1.289 times more likely to be depressed (B=1.289, p<.000), and 1.399 times more likely to have generalized anxiety disorder (B=1.399, p<.000) was highly likely to experience it. Additionally, factors affecting the mental health of adolescents with allergic diseases were gender, economic level, academic performance, drinking experience, and smoking experience. Stress and generalized anxiety disorder were more likely to be experienced by female students, if they had a lower economic level and academic performance, and if they drank alcohol or smoked. Male students were more likely to experience depression if their economic level and academic performance were higher, and if they did not drink alcohol or smoke. Based on these results, we hope to establish a practical approach by establishing effective strategies to manage allergic diseases in adolescents and the mental health conditions that may arise from them.

• Journal of the Korean Society of School Health
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• v.11 no.2
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• pp.171-187
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• 1998

In recent years, adolescent issues including smoking, drinking, drug abuse, juvenile delinquency, deviant sexual behavior, mental health problems, high suicide rate, juvenile delinquency and absence without due notice, etc are emerging as serious social problems and the debate on these controversial issues is heating up. The previous studies on adolescent health behavior and social juvenile delinquency such as run-away from home and absence without due notice have been conducted mostly by cause analysis utilizing social demographic factors or biological factors. In other words, the main factors analyzed were demographic and economic factors or parent's educational level, etc, which were the fixed environmental ones that were unable to cause the change in the health behavior. Accordingly, the purpose of this study is to analyze factors which are changeable and fixable among the factors influencing the adolescent's health behavior and misconducts and, eventually influencing factors which can be used as the basis to establish health policies and health promotion program to reduce the health risk behavior and misconducts of adolescents. The study subjects were selected by dividing senior high school student in Seoul by region and through random sampling. The 890 subjects were selected from 10 schools including the preparatory school, vocational schools and institutional schools. The duration of the study was for July 1-5, 1997 for the first survey and the second one, for August 25-September 10. Regarding the analysis method, the SAS program was used. The adoptablity of theoretical model was tested through covariance structural analysis utilizing PC-LISREL 8.12 Program. The major findings of the study are as follows: As a result of establishing the model of factors influencing health behavior and juvenile delinquency, in case of male students as the health behavior self-efficacy, education level of fathers, economic level, self-control and the health interest of parent were higher, students were more likely to practice the health promoting behavior. Juvenile delinquency and health risk behavior were prevalent among those with the less shyness, the lower health behavior self-efficacy, lower self-control, lower self-assertiveness, lower economic level. The self-control was the most powerful factor. In case of female students, those with higher health behavior self-efficacy were more likely to practice the health promoting behavior whereas those with lower health behavior self-efficacy, lower self-control, lower self- assertiveness, less shyness were more likely to practice health risk behavior and juvenile delinquency. In case of prep schools, those with higher health behavior self-efficacy and better perceived health status were more likely to practice the health promoting behavior while those with less shyness, lower health behavior self-efficacy and lower academic achievement were more likely to engage in health risk behavior and juvenile delinquency. In case of vocational schools, as health behavior self-efficacy and economic level were higher, the practice rate of health promoting behavior was higher. As the self-control, shyness, self-assertiveness, health behavior self-efficacy were lower, the rate of health risk behavior and juvenile delinquency were higher. In case of social institutional schools, as, the health behavior self-efficacy, social support and economic level, health interest of parents were higher, the rate of health promoting behavior were higher. As the self-control, shyness, self-assertiveness, health behavior self-efficacy and social support were lower, the rate of health risk behavior and juvenile delinquency were higher. So the health promoting behavior was positively related to the health behavior self-efficacy, health interest of parents, social support, education level of fathers, level of perceived health status, economic level. The health risk behavior and juvenile delinquency were higher with the lower health behavior self-efficacy, self-control and self-assertiveness, lower health locus control, less shyness and loneliness, lower economic level and academic achievement. In conclusion, the health risk behavior and juvenile delinquency can be reduced by enhancing self-control, self-assertiveness, health behavior self-efficacy and social support. According to the final model drawn by connecting health behavior and juvenile delinquency, the reduction of health risk behavior can greatly contribute to decreasing social juvenile delinquency as the process of juvenile delinquency was extended from common behaviors to problem behaviors and further into juvenile delinquency.