• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1125-1146
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• 2018

Segment lining applied to the TBM tunnel is mainly made of concrete, and it requires sufficient structural capacity to resist loads received during the construction and also after the completion. When segment lining is design to the Limit State Design, both Ultimate Limit State (ULS) and Service Limit State (SLS) should be met for the possible load cases that covers both permanent and temporary load cases - such as load applied by TBM. When design segment lining, it is important to check structural capacity at the joints as both temporary and permanent loads are always transferred through the segment joints, and sometimes the load applied to the joint is high enough to damage the segment - so called bursting failure. According to the various design guides from UK (PAS 8810, 2016), compression stress at the joint surface can generate bursting failure of the segment. This is normally from the TBM's jacking force applied at the circumferential joint, and the lining's hoop thrust generated from the permanent loads applied at the radial joint. Therefore, precast concrete segment lining's joints shall be designed to have sufficient structural capacity to resist bursting stresses generated by the TBM's jacking force and by the hoop thrust. In this study, bursting stress at the segment joints are calculated, and the joint's structural capacity was assessed using Leonhardt (1964) and FEM analysis for three different design cases. For those three analysis cases, hoop thrust at the radial joint was calculated with the application of the most widely used limit state design codes Eurocode and AASHTO LRFD (2017). For the circumferential joints bursting design, an assumed TBM jack force was used with considering of the construction tolerance of the segments and the eccentricity of the jack's position. The analysis results show reinforcement is needed as joint bursting stresses exceeds the allowable tensile strength of concrete. This highlights that joint bursting check shall be considered as a mandatory design item in the limit state design of the segment lining.

• Journal of Nutrition and Health
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• v.51 no.6
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• pp.538-555
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• 2018

Purpose: This study examined the association of the type and frequency of coffee consumption with the health-related quality of life and metabolic bio-markers in adult men and women from the 2013 ~ 2016 Korea National Health and Nutrition Examination Survey (KNHANES). Methods: A total of 11,201 subjects (4,483 men and 6,718 women) were classified according to the type of coffee consumption (non-coffee, black coffee, 3-in-1 coffee) and type and frequency of coffee consumption (non-coffee, ${\leq}2$ times/day of black coffee, > 2 times/day of black coffee, ${\leq}2$ times/day of 3-in-1 coffee, > 2 times/day of 3-in-1 coffee) using food frequency questionnaires. Dietary nutrient intake data were assessed using food frequency questionnaires. The health-related quality of life was measured using the EuroQol-5 dimension (EQ-5D) and EQ-5D index score. Data on metabolic bio-markers were obtained from a health examination. Results: Among men and women, the proportion of subjects with an energy intake below the estimated energy requirement (EER) was lower among the 3-in-1 coffee consumption group, and the proportion of subjects with iron intakes below the estimated average requirements (EAR) was lower among the 3-in-1 coffee consumption group. Women (OR: 0.810, 95% CI: 0.657 ~ 0.998) with the ${\leq}2$ times/day of 3-in-1 coffee had a lower risk of impaired health-related quality of life (lowest 20% level in the EQ-5D score) compared to the non-coffee consumers after a multivariable adjustment. In both men and women, the type and frequency of coffee consumption was not associated with metabolic bio-markers risk after multivariable adjustment. Conclusion: These results suggest that 3-in-1 coffee consumption may be associated with a lower risk of impaired health-related quality of life and may not be associated with the metabolic bio-markers risk in adult men and women.

• Korean Journal of Psychosomatic Medicine
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• v.29 no.1
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• pp.17-25
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• 2021

Objectives : This study aimed to investigate quality of life, severity of depression, suicidality, subjective health and subjective stress of depression with subjective cognitive decline in Korean adults. Methods : We used the 7th KNHANES data to enroll 415 participants with a score of 10 or higher on Patient Health Questionnaire-9 (PHQ-9), aged 20-64. Depression was divided into two groups based on the presence/absence of subjective cognitive decline. Demographic and psychological characteristics were compared between two groups. Correlation analysis of subjective cognitive decline, quality of life, depression, suicidal idea was carried out. To detect which variables influenced quality of life, a multiple regression analysis was carried out. Results : Among the 415 participants, 98 had depression with subjective cognitive decline. We identified significant differences in age, marital status, education, employment between the two groups. After adjusting for these variables, depression with subjective cognitive decline had lower EuroQol-5D index scores, more severe depressive symptoms without cognition and worse subjective health than depression without cognitive decline. There was a significant correlation between subjective cognitive decline and quality of life (r=-0.236, p<0.001), suicidal idea (r=0.182, p<0.001), depression score without cognition (r=0.108, p=0.028). Through multiple regression analysis, subjective cognitive decline was predictor of reduced quality of life (β=-0.178, p<0.001). Conclusions : Depression with subjective cognitive decline has poor quality of life and severe depression. Cognitive decline should be considered to improve treatment result in depression.