• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.643-653
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• 2013

Recently, there are an increasing number of studies on the method of wrapping the outer wall of granular piles with geosynthetic fibers such as geotextile or geogrid that has a certain level of tensile strength as an alternative method for the ground improvement techniques. In this study, triaxial compression tests are performed on the sand and clay specimen encased with various textiles to evaluate the reinforcing effect with regard to the tensile strength of the textile. Furthermore, triaxial compression tests are performed on the clay specimen inserted by sand only and sand encased with geosynthetics to compare behavioral differences between the conventional sand compaction pile and geosynthetic encased sand pile with regard to the replacement ratio, ${\alpha}_s$ and the tensile strength of the geosynthetics. Based on the experimental results, the strength enhancement due to the textile is affected by the longitudinal tensile strength rather than the transverse one of the applied textile. The effect of the confinement by the textile encasement results in the large increase of the cohesions. The overall behaviors, such as shear strength, pore pressure parameter at failure and stress ratio, of the geosynthetic encased sand pile is quite different from those of the conventional sand compaction pile.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.468-476
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• 2020

This study investigated how latent groups depend on the longitudinal trajectories observed in fathers' involvement in parenting over a five year period, and the study also determined differences in children's behavioral problems and mother's parenting stress, marital satisfaction, and depression among these groups. By utilizing 1,316 sets of data from 1st to 5th Panel Survey of PSKC beginning in 2008, we examined the patterns of the latent groups and the differences among them. The results showed that, first, a changing pattern of fathers' involvement in parenting is classified into four groups: a low-stable group, a decreasing group. a middle-high changeable group, and a highest changeable group. According to the results of the latent groups, the fathers' involvement in parenting commonly started to decrease at the children's age of 4 years old. Second, problematic behaviors of children appeared more from the fathers in the decreasing group. Third, parenting stress, marital conflict, and depression were more often found in the low-stable group that in the decreasing group. the middle-high changeable group and the highest changeable group (in that order), while marital satisfaction showed a completely opposite pattern. Based on these results, political intervention and the future direction of research for fathers' involvement in parenting are needed in order to increase better behaviors of their children as well as the psychological well-being of their mothers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.554-561
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• 2016

In this study, loading tests and a strength evaluation of the bogie frame were conducted to verify the structural safety of the bogie system in an intermodal tram, which runs with cars on a road track. The loads were calculated taking into account the features of the road track with many sharp curves and steep gradients, which are different from the track of conventional railway. They were compared with the loads specified in the previous standard specifications. After the comparison, it was confirmed that the loads acting on the bogie system operating on a road track are slightly different from the specified loads. The specified vertical load of the standard specification for all kinds of trains is conservative, but the specified lateral and longitudinal loads are less than the calculated loads. The application of the actual loads was proven to be reasonable in the development of a new railway system. Based on the defined loads, the bogie frame was fabricated on which strain gauges were attached. It was set on the large loading frame so that the stresses could be measured when loads were applied by hydraulic actuators. After measuring the stresses, it was shown that they were below the allowable stress, which verified the structural safety of the bogie frame.

• Korean Journal of Culture and Social Issue
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• v.29 no.3
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• pp.321-340
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• 2023

This study was conducted to understand the emotional and situational context where non-suicidal self-injury occurs in everyday life. Sixty adults(age 19-35) completed daily surveys assessing positive and negative emotions, stressful events, self-injury thoughts, and behaviors for two weeks. Using a total of 663 collected entries, we analyzed specific personal emotions and stressful events related to non-suicidal self-injurious thoughts and behaviors. As a result, high negative emotions, low positive emotions, and total stress event scores were significantly related to self-injury thoughts and behaviors. In the model in which both emotion and stress were inserted as predictors, the low level of positive emotion showed a significant related to non-suicidal self-injurious behavior. These results suggest that negative emotion management and overall positive emotion reinforcement are important in emotion regulation intervention for non-suicidal self-injurious patients. The meaning of this study is that it searched for risk factors of non-suicidal injury in everyday life using a short-term longitudinal method.

• Sleep Medicine and Psychophysiology
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• v.24 no.1
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• pp.38-45
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• 2017

Objectives: Sleep disturbance is a very rapidly growing disease with aging. The purpose of this study was to investigate the prevalence of sleep disturbances and its predictive factors in a three-year cohort study of people aged 60 years and over in Korea. Methods: In 2012 and 2014, we obtained data from a survey of the Korean Social Life, Health, and Aging Project. We asked participants if they had been diagnosed with stroke, myocardial infarction, angina pectoris, arthritis, pulmonary tuberculosis, asthma, cataract, glaucoma, hepatitis B, urinary incontinence, prostate hypertrophy, cancer, osteoporosis, hypertension, diabetes, hyperlipidemia, or metabolic syndrome. Cognitive function was assessed using the Mini-Mental State Examination for dementia screening in 2012, and depression was assessed using the Center for Epidemiologic Studies Depression Scale in 2012 and 2014. In 2015, a structured clinical interview for Axis I psychiatric disorders was administered to 235 people, and sleep disturbance was assessed using the Pittsburgh Sleep Quality Index. The perceived stress scale and the State-trait Anger Expression Inventory were also administered. Logistic regression analysis was used to predict sleep disturbance by gender, age, education, depression score, number of coexisting diseases in 2012 and 2014, current anger score, and perceived stress score. Results: Twenty-seven percent of the participants had sleep disturbances. Logistic regression analysis showed that the number of medical diseases three years ago, the depression score one year ago, and the current perceived stress significantly predicted sleep disturbances. Conclusion: Comorbid medical disease three years previous and depressive symptoms evaluated one year previous were predictive of current sleep disturbances. Further studies are needed to determine whether treatment of medical disease and depressive symptoms can improve sleep disturbances.

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.71-82
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• 2006

One of the most popular pre-reinforcement methods of tunnel heading in cohesionless soils would be the fore-polling of grouted pipes, known as RPUM (reinforced protective umbrella method) or UAM (umbrella arch method). This technique allows safe excavation even in poor ground conditions by creating longitudinal arch parallel to the tunnel axis as the tunnel advances. Some previous studies on the reinforcing effects have been performed using numerical methods and/or laboratory-based small scale model tests. The complexity of boundary conditions imposes difficulties in representing the tunnelling procedure in laboratory tests and theoretical approaches. Full-scale study to identify reinforcing effects of the tunnel heading has rarely been carried out so far. In this study, a large scale model testing for a tunnel in granular soils was performed. Reinforcing patterns considered are four cases, Non-Reinforced, Crown-Reinforced, Crown & Face-Reinforced, and Face-Reinforced. The behavior of ground and pipes as reinforcing member were fully measured as the surcharge pressure applied. The influences of reinforcing pattern, pipe length, and face reinforcement were investigated in terms of stress and displacement. It is revealed that only the Face-Reinforced has decreased sufficiently both vertical settlement in tunnel heading and horizontal displacement on the face. Vertical stresses along the tunnel axis were concentrated in tunnel heading from the test results, so the heading should be reinforced before tunnel advancing. Most of maximum axial forces and bending moments for Crown-reinforced were measured at 0.75D from the face. Also it should be recommended that the minimum length of the pipe is more than l.0D for crown reinforcement.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.1
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• pp.57-70
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• 2009

Considerable advance has been made on research on effect of steel pipe Umbrella Arch Method (UAM) and mechanical reinforcement mechanism through numerical analyses and experiments. Due to long analysis time of three-dimensional analysis and its complexity, un-quantitative two-dimensional analysis is dominantly used in the design and application, where equivalent material properties of UAM reinforced area and ground are used, For this reason, development of reasonable, theoretical, quantitative and easy to use design and analysis method is required. In this study, both field UAM tests and laboratory tests were performed in the residual soil to highly weathered rock; field tests to observe the range of reinforcement, and laboratory tests to investigate the change of material properties between prior to and after UAM reinforcement. It has been observed that the increase in material property of neighboring ground is negligible, and that only stiffness of steel pipe and cement column formed inside the steel pipe and the gap between steel pipe and borehole contributes to ground reinforcement. Based on these results and concept of Convergence Confinement Method (CCM), two dimensional axisymmetric analyses have been performed to obtain the longitudinal displacement profile (LDP) corresponding to arching effect of tunnel face, UAM effect and effect of supports. In addition, modified load distribution method in two dimensional plane-strain analysis has been suggested, in which effect of UAM is transformed to internal pressure and modified load distribution ratios are suggested. Comparison between the modified method and conventional method shows that larger displacement occur in the conventional method than that in the modified method although it may be different depending on ground condition, depth and size of tunnel, types of steel pipe and initial stress state. Consequently, it can be concluded that the effect of UAM as a beam in a longitudinal direction is not considered properly in the conventional method.

• Development and Reproduction
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• v.16 no.3
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• pp.227-233
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• 2012

Circadian timing system plays a major role in a wide range of reproductive function. However it is plausible idea that other environmental and/or internal cue might be simultaneously participated in the optimal regulation of reproductive system. In the present study we extended the reverse feeding (RF) time regimen up to 8 weeks, then measured the general and reproductive indices of the animals. The animals of ad libitum feeding group (Control, CON) have free access to food for 4, 6 and 8 weeks, respectively. The day feeding animals (reverse feeding, RF group) have restricted access to food during daytime (09:00-18:00) for 4, 6 and 8 weeks, respectively. When the feeding schedules were over, key indices were measured. After 4 weeks and 8 weeks of feeding, body weights of animals were not significantly different. However, body weights of 6 weeks RF animals were significantly smaller than those of control animals (CON : RF = $333.46{\pm}12.71$ g : $289.91{\pm}8.31$ g, p<0.01). The blood glucose levels of 4 weeks RF animals were significantly decreased compared to the levels of control animals (CON : RF = $161.4{\pm}2.7$ mg/dL : $176.7{\pm}5$ mg/dL, p<0.01) while the levels of 6 weeks RF and 8 weeks RF animals were not different form those of control animals. Reproductive and non-reproductive tissue weights from 6 weeks RF group were significantly lowered than those from CON group (testis, CON : RF = $1.4714{\pm}0.0174$ g : $1.3724{\pm}0.0168$ g, p<0.001; epididymis, CON : RF = $0.3574{\pm}0.0059$ g : $0.3243{\pm}0.0068$ g, p<0.001; seminal vesicle, CON : RF = $0.1655{\pm}0.0068$ g : $0.1328{\pm}0.0054$ g, p<0.001; prostate, CON : RF = $0.3350{\pm}0.0231$ g : $0.2528{\pm}0.0143$ g, p<0.01). After 4 weeks and 8 weeks of reverse feeding, sperm counts in RF animals were markedly reduced than those in control animals[CON 4W : RF 4W = $121.17{\pm}9.96\;({\times}10^6)$ : $50.86{\pm}9\;({\times}10^6)$, p<0.001; CON 8W : RF 8W= $138.69{\pm}9.8\;({\times}10^6)$ : $108.94{\pm}4.22\;({\times}10^6)$, p<0.001]. Present study indicates that RF may induce an adaptable metabolic stress and cause impairment of androgen-dependent reproductive tissues. On-going longitudinal studies will allow a better understanding of the how does mealtime shift affect the reproductive function and exact nature of adaptation.

• Journal of Preventive Medicine and Public Health
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• v.49 no.4
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• pp.220-229
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• 2016

Objectives: The association between educational status and 10-year risk for acute coronary syndrome (ACS) and all-cause mortality was evaluated. Methods: From October 2003 to September 2004, 2172 consecutive ACS patients from six Greek hospitals were enrolled. In 2013 to 2014, a 10-year follow-up (2004-2014) assessment was performed for 1918 participants (participation rate, 88%). Each patient's educational status was classified as low (<9 years of school), intermediate (9 to 14 years), or high (>14 years). Results: Overall all-cause mortality was almost twofold higher in the low-education group than in the intermediate-education and high-education groups (40% vs. 22% and 19%, respectively, p<0.001). Additionally, 10-year recurrent ACS events (fatal and non-fatal) were more common in the low-education group than in the intermediate-education and high-education groups (42% vs. 30% and 35%, p<0.001), and no interactions between sex and education on the investigated outcomes were observed. Moreover, patients in the high-education group were more physically active, had a better financial status, and were less likely to have hypertension, diabetes, or ACS than the participants with the least education (p<0.001); however, when those characteristics and lifestyle habits were accounted for, no moderating effects regarding the relationship of educational status with all-cause mortality and ACS events were observed. Conclusions: A U-shaped association may be proposed for the relationship between ACS prognosis and educational status, with participants in the low-education and high-education groups being negatively affected by other factors (e.g., job stress, depression, or loneliness). Public health policies should be aimed at specific social groups to reduce the overall burden of cardiovascular disease morbidity.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.601-609
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• 2008

The purpose of this study is to investigate the flexural strengthening effectiveness for the beams combined reinforced with NSM CFRP strips and EBR CFRP strips. To accomplish this objective, a total of nine concrete T beams were tested. From this study, it is found that the flexural stiffness and strength of the beams combined reinforced with NSM and EBR strips were significantly improved compared to the beams strengthened only with NSM CFRP strip. The maximum increase of flexural strength was 347% compared to the beam without CFRP strip. Failure of the beam combined reinforced with NSM and EBR strips (T shape) is initiated by debonding of EBR strips attached on the bottom face, and it was succeeded a part of separatio-n of NSM strips along the longitudinal direction and secondly failure of NSM strips was occurred, eventually sudden explosive failure with the separation of concrete cover in the shear region. This result shows that the NSM and EBR strips have good combination to resist applied load and the combined reinforcement with NSM and EBR strips can redistribute appropriately the total stress subjected concrete beam to the EBR and NSM strips.