• Journal of Ship and Ocean Technology
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• v.8 no.3
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• pp.26-39
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• 2004

A vessel/mooring/riser coupled dynamic analysis program in time domain is developed for the global motion simulation of a turret-moored, tanker based FPSO designed for 6000-ft water depth. The vessel global motions and mooring tension are simulated for the non-parallel wind-wave-current 100-year hurricane condition in the Gulf of Mexico. The wind and current forces and moments are estimated from the OCIMF empirical data base for the given loading condition. The numerical results are compared with the OTRC(Offshore Technology Research Center: Model Basin for Offshore Platforms in Texas A&M University) 1:60 model-testing results with truncated mooring system. The system's stiffness and line tension as well as natural periods and damping obtained from the OTRC measurement are checked through numerically simulated static-offset and free-decay tests. The global vessel motion simulations in the hurricane condition were conducted by varying lateral and longitudinal hull drag coefficients, different mooring and riser set up, and wind-exposed areas to better understand the sensitivity of the FPSO responses against empirical parameters. It is particularly stressed that the dynamic mooring tension can be greatly underestimated when truncated mooring system is used.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.225-230
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• 2009

From the view point of railway vehicle dynamics, the interaction between wheel and rail have an huge effect on the behavior of the vehicle. This phenomenon is an unique motion, only for railway vehicles. Furthermore, close investigation of the backgrounds of the interaction is the key to estimate the dynamic behavior of the vehicle, successfully. To evaluate the model including flexible bodies such as car body and catenary system of the next generation express train, it is necessary to develop proper dynamic solver including a wheel rail contact module. In this study, wheel-rail contact module is developed using the general purpose dynamic solver. First of all, the procedure for calculation of the wheel-rail contact force has been established. Generally, yaw angle of the wheelset is ignored. Sets of information are summarized as tables and splined for further uses. With this information, normal force and creep coefficient can be extracted and used for FASTSIM algorithm, which has been shown good reliability over years. Normal force and longitudinal, lateral force at the contact surface are also calculated. Those data are verified by commercial railway simulation program 'VAMPIRE'. This procedure and program can offer a basic process for estimation of the dynamic behavior and wear of the wheel-rail system, even while running on the curved rail. Finally, multi-dimensional inspection tool will be developed including the prediction of the derailment.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.463-472
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• 2007

In this paper, the correlation between the vibration characteristics of the track components and the parameters affecting the vibration is analysed. To do it, the accelerations of each track component such as rails, sleepers and ballast are measured in Kyong-Bu high-speed line. The RMS values of the measured data are calculated and the pad stiffness, the longitudinal irregularity, running velocity and the corrugation, are considered as the parameters in the viewpoint of track. By using the linear regression, the correlation coefficient is calculated to analyse the relationship. Also, the 1/3 Octave analysis is calculated to analyse the dominant frequency band of tile vibrations of the track components.

• Journal of the Korean Society of School Health
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• v.20 no.1
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• pp.45-52
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• 2007

Purpose: The purpose of this study was to examine the types of school accidents and their first aids at Elementary, Middle, High Schools in a local area. Methods: The subjects were 1062 students who have had episodes of school accidents from 730 (Elementary = 429, Middle = 188, High = 113) schools in Chungnam province from January to December, 2006. Data were collected from accident-related record from school nurse and 'School Safety Fund', and analyzed using the SPSS Version 13.0 programs and the results and conclusions are as follows: Results: The proportion of school accidents occurred were in middle(0.43%), high(0.35%), primary(0.30%) school students. And the most frequent type of accident was fracture and then sprain. Most school accidents broke out in playground during resting time, and followed by physical education class. The most frequent cause of school accidents was carelessness and first aid was fixation the injury. Conclusion: Based on these findings, school-based and continuous safety education programs and emergency care system within school and in community can be suggested in collaboration with health-related resources. Further longitudinal study to identify causes and kinds of school accidents and can also be recommended.

• Korean Journal of Childcare and Education
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• v.17 no.5
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• pp.43-61
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• 2021

Objective: This study aimed to examine the sequential mediating effects of children's perceived maternal acceptance and peer acceptance in the relationship between maternal warmth and first grade children's school adjustment. Methods: Participants in this study were 979 seven-year-old children(498 boys, 481 girls) recruited for the Korea Child Panel Study. Data were analyzed by analyzing descriptive statistics, correlations, and significance of serial mediation pathways using SPSS 18.0 and PROCESS Macro 3.4. Results: Maternal warmth at age five effected perception of maternal acceptance at age six. Perceived maternal acceptance at age six effected perceived peer acceptance at age six. Perceived peer acceptance at age six effected school adjustment at age seven. Lastly, perceived maternal acceptance and peer acceptance at age six had a serial mediation effect between maternal warmth at age five and school adjustment at age seven. Conclusion/Implications: Perceived social acceptance during preschool years should be emphasized in order to promote school adjustment for first grade children. Parent education for promoting better parent child relationships should be considered and teachers should encourage peer play interaction to help children perceive acceptance from their peers.

• Structural Engineering and Mechanics
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• v.78 no.4
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• pp.413-423
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• 2021

Piers are the main lateral force-resisting members of high-speed railway (HSR) bridges used in China and are characterized by low axial load ratios, low longitudinal reinforcement ratios, low stirrup ratios, and high shear span ratios. It is well known that flexural, flexural-shear, and shear failures of piers may occur during an earthquake. In this study, a new shear strength model was developed to simulate the seismic failure of HSR solid piers accurately. First, low cyclic-loading test data of solid piers obtained in recent years were collected to set up a database for model verification. Second, based on the test database, the applicability of existing shear strength models was evaluated. Finally, a new shear strength model for HSR solid piers with round-ended cross-sections was derived based on the truss model and ultimate equilibrium theory. In comparison with existing models, it was demonstrated that the proposed model could be used to predict the shear strength of HSR piers more accurately.

• The Mathematical Education
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• v.57 no.4
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• pp.393-412
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• 2018

Teacher quality is a key factor that determines quality of education. Being aware of this, the Korean government and teachers have been striving to improve teachers' professionalism. Research about the impacts of efforts to enhance teacher professionalism on students' academic achievement and course satisfaction, however, is extremely limited. This study sought to advance our understanding of the relationship between these factors by analyzing what teacher characteristics impact students' achievement and satisfaction. To this end, the study drew on the middle and high school data from 3rd to 6th year survey of the Seoul Educational Longitudinal Study. Structural equational modeling were used as the main approach. Latent profile analysis, a kind of mixture modeling analysis, were used as needed. This study found that teachers' participation in instruction enhancement activity and professional development impact students' attitude toward mathematics lessons and their perception on class atmosphere, and ultimately impact their academic achievement as well as their overall satisfaction in the course. In addition, teachers' use of EBS textbooks and videos impact 3rd grade high schoolers' academic achievement. These findings suggest that effort to improve teacher professionalism positively impact students' academic achievement and course satisfaction, although there is a difference according to the year grade. This study provides implications for education policy makers and teacher educators.

• Journal of Society of Preventive Korean Medicine
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• v.23 no.2
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• pp.11-23
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• 2019

Objectives : The purpose of this study was to explore factors related quality of life among cancer survivor in order to identify strategies for cancer survivors to go back to normal life and carry on stable and high quality life. Methods : This study used the $1^{st}$ to $6^{th}$ data of Korean Longitudinal Study of Aging(KLoSA). The sample of this study consisted of 118 cancer survivors, all of whom were diagnosed with cancer for more than 10 years later in 2016. Results : Regression analysis of major factors related to the quality of life of elderly cancer survivors showed that the results of 2006 and 2016 were different. In 2006, factors related to cancer were highly correlated with quality of life, but in 2016, it was associated with pain and depression. Conclusions : The results of this study confirm that the factors related to quality of life in cancer survivors change with survival period. Therefore, this study suggests comprehensive care strategies based on the stage of survivorship.

• Journal of Korean Critical Care Nursing
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• v.12 no.1
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• pp.22-35
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• 2019

Purpose : This study was to determine the levels of environmental stressor, posttraumatic stress disorder, and quality of life in intensive care units (ICU) survivors after intensive care, and to explore the factors affecting posttraumatic stress disorder and quality of life. Methods: With a longitudinal survey design, data were collected from 116 patients who were discharged from the ICU of a university hospital. The environmental stressor, posttraumatic stress disorder, and quality of life were measured immediately following and 1 month after the ICU discharge. Results: Of all the subjects, 16.4% experienced posttraumatic stress disorder after discharge. Multiple regression analysis revealed that ICU environmental stressors, experience of ICU readmission, using psychotropic drugs and narcotic analgesics, and ICU admission after surgery or cardiac intervention accounted for 22.2% of posttraumatic stress disorder. Posttraumatic stress disorder and sedation status when entering ICU accounted for 28.3% of the quality of life 1 month after ICU discharge. Conclusion: Nursing interventions focused on ICU environmental stressors would not only reduce environmental stress but also contribute to the reduction of posttraumatic stress disorder and later improvement of quality of life.

• Computers and Concrete
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• v.22 no.6
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• pp.527-538
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• 2018

Buckling of longitudinal bars is a brittle failure mechanism, often recorded in reinforced concrete (RC) structures after an earthquake. Studies in the literature highlights that it often occurs when steel is in the post elastic range, by inducing a modification of the engineered stress-strain law of steel in compression. A proper evaluation of this effect is of fundamental importance for correctly evaluating capacity and ductility of structures. Significant errors can be obtained in terms of ultimate bending moment and curvature ductility of an RC section if these effects are not accounted, as well as incorrect evaluations are achieved by non-linear static analyses. This paper presents a numerical investigation aiming to evaluate the engineered stress-strain law of reinforcing steel in compression, including second order effects. Non-linear FE analyses are performed under the assumption of local buckling. A role of key parameters is evaluated, making difference between steel with strain hardening or with perfectly plastic behaviour. Comparisons with experimental data available in the literature confirm the accuracy of the achieved results and make it possible to formulate recommendations for design purposes. Finally, comparisons are made with analytical formulations available in the literature and based on obtained results, a modification of the stress-strain law model of Dhakal and Maekawa (2002) is proposed for fitting the numerical predictions.