• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.143-147
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• 2010

Chronic exposure to Arsenic (As) causes significant human health effects including various cancers. Total As concentrations from 300 polished rice samples cultivated near the mining areas in Korea were analyzed to estimate a probabilistic assessment of human health risk from As-contaminated rice. The mean of total As concentrations in rice was 0.09 mg/kg and lognormal distribution model was set for total As concentrations. Human health risk for As in rice was estimated using gender-specific rice consumption data and average daily dose (ADD). While cancer risk (CR) and hazard quotient (HQ) were calculated using oral cancer slope factor (OCSF) and Reference dose (RfD) suggested by the U.S. EPA. Mean of CR posed by total As was 2.16 (for male) and 1.83 (for female) per 10,000. The HQ for general population from rice cultivated near the mining areas in Korea was below 1 as the $50^{th}$ percentile of general population. However, less than 10% of general population consuming rice cultivated near the mining areas would exceed 1.0. This result is similar with those from each gender-specific group.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.267-273
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• 2000

Temperature-associated emergence patterns for a hydropsychid caddisfly, Hydropsyche kozhantschikovi, were studied from the Wangsuk creek in Kyonggi-do from April to June in 1999. Emerging adults were quantitatively collected by pyramidshaped emergence traps. Water temperature was hourly monitored in 1999. The emergence began at April 15 when the daily mean water temperature rose to ca. $10^{\circ}C$: it rapidly increased and peaked in ca. 10 days, and continued to May 25, lasting 40 days since the starting date. The average number of emerged adults was $35.8\;inds./m^2$ and their sex ratio was male (M) : female (F) = 1 : 2.04. The emergence of males was ca. 2 days earlier than that of females. Daily, the emergence was a bigeminans pattern representing the major peak (66.7%) just after dark ($19:00{\sim}21:00$) and theminor peak (11.1%) just before dawn ($05:00{\sim}07:00$). According to our degree dayaccumulation (DD) model, it respectively required 453.89DD (M: 440.48DD and F: 473.97 DD), 615.71DD (M: 610.18DD and F: 622.09DD), and 820.24DD (M: 828.25DD and F: 804.71DD) to begin, to reach the peak, and to finish the emergence.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.443-451
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• 2021

The purpose of this study is to investigate the mediating effects of depression, academic helplessness, and smartphone addiction tendency in the relationship between self-esteem and grit of adolescents. Data from the 2018 (first-year) Korean Children and Youth Panel Survey were used in this study. The subjects of this study were 1,375 male and 1,166 female students in seventh grade school. The multiple mediation model analysis was conducted using the SPSS and PROCESS macro program. The results of this study are as follows. First, there was a positive correlation between self-esteem and grit, while self-esteem and grit had negative correlations with depression, academic helplessness, smartphone addiction. Second, it was found that the relationship between self-esteem and grit was mediated by depression, academic helplessness, and smartphone addiction tendency, respectively, and furthermore, it was found that all pathways mediated sequentially were also significant. These results suggest that education and intervention considering self-esteem, depression, academic helplessness, and smartphone addiction to be useful as a way to help adolescents develop interest in specific goals and continue their efforts in these days when smartphone use is common.

• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.777-789
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• 2020

COVID-19 has been rapidly spread world wide since late December 2019. In this paper, our interest is to estimate distribution of incubation time defined as period between infection of virus and the onset. Due to the limit of accessibility and asymptomatic feature of COVID-19 virus, the exact infection and onset time are not always observable. For estimation of incubation time, interval censoring technique is implemented. Furthermore, a competing risk model is applied to estimate the case fatality and cure fraction. Based on the result, the mean incubation time is about 5.4 days and the fatality rate is higher for older and male patient and the cure rate is higher at younger,female and asymptomatic patient.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.3
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• pp.96-106
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• 2014

Necessarily traffic policies have been biased in car than pedestrian, so pedestrian's environment is getting worse. Result of this situation our accident rate is high as 36.4%, compared to OECD member countries with average rate of 17.8%(in 2009). Increasing interest for pedestrians environment improvement, and it make an effort to build environment to guarantee walk and safety of pedestrians. Analysis on the binary logistic regression(BLR) was used. The dependent variable is occurring from the road width of less than 9m accident, and independent variable extracted can be obtained from the traffic accident data. Traffic accident on roads having width of less than 9 meters affecting variables is when the driver is straight, when the driver is female, when the pedestrian is walk driveway, and so on. To prevent it, efforts is demanded to protect handicapped, to build safe pedestrians environment using C-ITS and to decrease speed of going straight vehicle on roads having width of less than 9 meters.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.4
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• pp.377-383
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• 2021

Purpose: We investigated the association of effector memory (EM) CD8⁺ T cell and CD4⁺ T cell immunity with metabolic syndrome (MS). Methods: Surface and intracellular staining of peripheral blood mononuclear cells was performed. Anti-interleukin-7 receptor-alpha (IL-7Rα) and CX3CR1 antibodies were used to stain the subsets of EM CD8⁺ T cells, while anti-interferon-gamma (IFN-γ), interleukin-17 (IL-17), and forkhead box P3 (FOXP3) antibodies were used for CD4⁺ T cell subsets. Results: Of the 47 obese children, 11 were female. Children with MS had significantly higher levels of serum insulin (34.8±13.8 vs. 16.4±6.3 µU/mL, p<0.001) and homeostasis model assessment of insulin resistance (8.9±4.1 vs. 3.9±1.5, p<0.001) than children without MS. Children with MS revealed significantly higher frequencies of IL-7Rα^low CD8⁺ T cells (60.1±19.1% vs. 48.4±11.5%, p=0.047) and IL-7Rα^lowCX3CR1⁺ CD8⁺ T cells (53.8±20.1% vs. 41.5±11.9%, p=0.036) than children without MS. As the serum triglyceride levels increased, the frequency of IL-7Rα^lowCX3CR1⁺ and IL-7Rα^highCX3CR1^- CD8⁺ T cells increased and decreased, respectively (r=0.335, p=0.014 and r=-0.350, p=0.010, respectively), in 47 children. However, no CD4⁺ T cell subset parameters were significantly different between children with and without MS. Conclusion: In obese children with MS, the changes in immunity due to changes in EM CD8⁺ T cells might be related to the morbidity of obesity.

• Korean Journal of Environment and Ecology
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• v.27 no.3
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• pp.396-404
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• 2013

The purpose of this study is to propose the method to improve management aspect and facilities plan to enhance spatial cognition of visitors through visitors' analysis of spatial cognition regarding tourism destination facilities. The research model was established by factors affecting spatial cognition such as facilities characteristics and visitor characteristics as well as spatial cognition of visitors' facilities to achieve objectives of research, and actual proof analysis was made to visitors to Nami Island tourism destination based of this. As a result of analysis, it was proved that visitor characteristics including their gender and age, and tour map use as well as facilities characteristics of facilities type, location, etc showed a statistically significant difference in visitors' spatial cognition. In addition, it is deemed as a result of analysis that Nami Island requires re-organization of symbolic features and attractiveness of food and beverage facility, while needing additional installment and rearrangement of information facilities and related facilities. The result of this research suggests that close analysis and application of factors affect spatial cognition such as facilities and visitors' characteristics to plan and manage the tourism destination facilities effectively. Moreover, visitors' spatial cognition is related to spatial characteristics of tourism destination, therefore it is analyzed that the uniqueness of facilities played an important role in improving female's spatial cognition. In particular, the result of this study is meaningful in that in light of plan and management for tourism destination facilities, the function to provide tourism destination plays a major role in improving visitors' spatial cognition regardless of complexity of spatial structure of tourism destination.

• Journal of Korean Society of Transportation
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• v.32 no.4
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• pp.347-356
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• 2014

Passenger cars occupy about 74% among registered vehicles in Korea and the ratio of transportation mode sharing is approximately 60% in the passenger transport part. However, there is no statistics related to travel characteristics of passenger cars, and official statistics are estimated from O/D travel data. Thus, National Transportation DataBase Center in KOTI has attempted to construct various statistical data through Korea Vehicle Use Survey. Based on these data, Analysis of Variance (ANOVA) was conducted to investigate the differences in travel characteristics of each analysis group. As a result, all of the explanatory variables(weekday vs. weekend, metropolitan area vs. non-metropolitan area, male vs. female, commute time vs. other time, routine purpose vs. non-routine purpose) were found to be different across households. In addition, travel distances per trip of weekday, metropolitan area, male, commute time, and non-routine purpose are longer than the opposite variables. Also, the trip distances of small size(1 to 2 persons) households are shorter compared to large size(more than 5 persons) households.

• Journal of the Korean Society of Child Welfare
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• no.36
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• pp.133-163
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• 2011

The aim of this study is to examine the relationships between social support and child behavior problems and cognitive development in low income female-headed families. Informed by the stress-coping theory, family process model, and theoretical perspectives related to social support, this study estimates both direct and indirect effects of social support on child behavior problems and cognitive development. In particular, we focus on how the relationship between child outcomes and social support is mediated by mothers' parenting stress. The first three waves of longitudinal data from a subsample of 1,315 single and non-cohabiting low-income mothers in the Fragile Families and Child Wellbeing Study were utilized in this study. Results suggest that social support is directly associated with child behavior problems and also indirectly associated with child behavior problems mediated by mothers' parenting stress. Social support did not have a direct effect on children's cognitive development but rather had an indirect effect, which was mediated by mothers' parenting stress. The policy and practice implications of these findings are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.206-217
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• 2017

The purpose of this study was to explore the causal relationships between turnover intention and its influencing factors among married female nurses. The participants included 148 married nurses at 5 general hospitals in J city. Data were collected by using self-reported questionnaires and were analyzed by using SPSS and AMOS software. The overall fitness of the modified path model to the data was good ($x^2/df=0.002$, GFI = 1.00, AGFI = 1.00, RMSEA = 0.00, NFI = 1.00, CFI = 1.00, TLI = 1.09). Job stress, social support, work-family conflict, and burnout explained 32.0% of the variance in turnover intention of the participants. In particular, work-family conflict had a complete mediating effect between job stress and burnout. In addition, work-family conflict had partial mediating effects between social support and burnout as well as between social support and turnover intention. Social support had direct and indirect effects on work-family conflict, burnout, and turnover intention. In conclusion, strategies for decreasing married nurses' burnout and turnover intention should focus on reducing work-family conflict and increasing social support.