• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.995-1001
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• 2001

The finite element human head model is developed for traumatic injury assessment. The model is constructed based on the precise anatomical geometry and validated with test results. In this paper, structural and physiologic explanation of human head will be introduced as well as the modeling methodology. Some of simulation results are also chosen to present major features of the model.

• Journal of Korean Academy of Nursing
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• v.48 no.1
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• pp.96-108
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• 2018

Purpose: This study aimed to construct and test a hypothetical model of the quality of life of school-age children with asthma based on the health-related quality of life model by Wilson and Cleary. Methods: Data were collected from 205 pairs of pediatric outpatients diagnosed with asthma and their parents in Seoul and Gyeonggi-do from July 2016 to April 2017. The exogenous variables were asthma knowledge, number of accompanying allergic diseases, and social support. The endogenous variables were asthma self-efficacy, asthma symptom control, perceived health status, parental quality of life, and children's quality of life. For data analysis, descriptive statistics, factor analysis, and structural equation modeling were performed. Results: Eighteen of the twenty-four hypotheses selected for the hypothetical model were attentive and supported statistically. Quality of life was explained by asthma self-efficacy, asthma symptom control, perceived health, parental quality of life, and asthma knowledge with 83.5%. Conclusion: Strategies for promoting self-efficacy and enforcing asthma knowledge will be helpful for the improvement of health-related quality of life with school-aged asthmatic children.

• Structural Engineering and Mechanics
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• v.27 no.6
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• pp.697-711
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• 2007

Though extensive research has been carried out for the ultimate strength of steel reinforced concrete (SRC) members under static and cyclic load, there was only limited information on the applied analysis models. Modeling of the inelastic response of SRC members can be accomplished by using a microcosmic model. However, generally used microcosmic model, which usually contains a group of parameters, is too complicated to apply in the nonlinear structural computation for large whole buildings. The intent of this paper is to develop an effective modeling approach for the reliable prediction of the inelastic response of SRC columns. Firstly, five SRC columns were tested under cyclic static load and constant axial force. Based on the experimental results, normalized trilinear skeleton curves were then put forward. Theoretical equation of normalizing point (ultimate strength point) was built up according to the load-bearing mechanism of RC columns and verified by the 5 specimens in this test and 14 SRC columns from parallel tests. Since no obvious strength deterioration and pinch effect were observed from the load-displacement curve, hysteresis rule considering only stiffness degradation was proposed through regression analysis. Compared with the experimental results, the applied analysis model is so reasonable to capture the overall cyclic response of SRC columns that it can be easily used in both static and dynamic analysis of the whole SRC structural systems.

• Research in Community and Public Health Nursing
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• v.30 no.3
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• pp.345-356
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• 2019

Purpose: The purpose of this study is to construct and test a structural equation model of posttraumatic growth (PTG) of earthquake victims based on Tedeschi and Calhoun's model (2004). Methods: Data were collected from 195 earthquake victims living in K. City. The exogenous variables include distress perception, resilience, and social support, and the endogenous variables include intrusive rumination, deliberate rumination, and posttraumatic growth. For data analysis, descriptive statistics, factor analysis, and structural equation modeling were performed. Results: The modified model showed a good fitness to the data. Moreover, 6 of the 9 paths of the final model were statistically significant, which include PTG affected by deliberate rumination (${\beta}=.58$, p<.001), resilience (${\gamma}=.18$, p=.001), and distress perception (${\gamma}=.20$, p=.002). These predictors explain 51.8% of variance in posttraumatic growth. Conclusion: Based on the results of this study, it is necessary to develop and disseminate preventive intervention programs to increase the resilience of earthquake-prone communities. In addition, after exposure to a community-scale traumatic event such as earthquake, we should provide social supports to alleviate distress perception and transition from intrusive rumination to deliberate rumination so that we can seek new meaning from the earthquake and facilitate posttraumatic growth.

• Journal of Korean Academy of Nursing
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• v.49 no.3
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• pp.241-253
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• 2019

Purpose: This study aimed to develop and test a model of the happiness of mothers with young children based on the stress-coping-adaptation model of Lazarus and Folkman. Methods: The data collection period was from May to July 2016. A self-report questionnaire was used to collect data from 210 mothers with children under 5 years of age living in Seoul, Gyeonggi, and Gangwon provinces. The exogenous variable was parenting stress, and the endogenous variables were parenting alliance, depression, optimism, ways of coping, and happiness. Data from 201 questionnaires were analyzed using the SPSS 22.0 and AMOS 20.0 programs. Data analyses included descriptive statistics, factor analysis, and structural equation modeling. Results: The final modified model showed a reasonable fit to the data, and out of 25 paths, 13 were statistically significant. This model explained 78.4% of the variance in the happiness of mothers with young children and confirmed that depression, optimism, parenting alliance, and social support-focused coping have a direct effect on the subject's happiness. Parenting stress also influenced happiness through parenting alliance, depression, and optimism. Conclusion: In order to bolster the happiness of mothers with young children, positive psychological interventions that can minimize psychological vulnerabilities, such as depression, and that can enhance their strengths, such as optimism, may serve as effective ways of coping with and adapting to stress.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.124-132
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• 2000

Distributed processing approach for structural optimization is presented in this study. It is implemented on network of personal computers. The validity and efficiency of this approach are demonstrated and verified by test model of truss. Repeated structural analysis algorithm, which spend a lot of overall structural optimization processes, are based on substructuring scheme with domain-wise parallelism and converted to be adapted to hardware and software environments. The design information data are modularized and assigned to each computer in order to minize the communication cost. The communications between nodes are limited to static condensation and constraint-related data collection.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.55-63
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• 2022

A modular underground arch structure using steel and concrete has been proposed as a structure that has a simple construction process and can effectively resist cross-sectional forces generated during construction and use. Structural behavior of modular underground arch was evaluated about span length less than 15m through 3D structural analysis and test. In general, 2D and 3D structural analysis methods may be applied for structural analysis such as underground arch and tunnels. However, if a 2D or 3D structural analysis method is applied to evaluate the structural safety of a modular underground arch structure, it is difficult to model for structural analysis and it may take an excessively long time to interpret. Therefore, it may not be reasonable as a structural analysis method for considering the structural safety and earth pressure in the design process of a modular underground arch structure. In addition, when a modular underground arch structure is configured for span lengths to which the predetermined cross-section is applicable, it may be reasonable to evaluate only the safety of the structure and cross-section according to the cross-section and load conditions. Therefore, in this study, a structural analysis model using frame elements was proposed for efficient structural safety evaluation. In addition, structural analysis results of the 2D structural analysis model and the simplified analysis model using frame elements were compared, and the structural safety of the modular underground arch structure for a span length of 20m was evaluated with a simplified analysis method.

• Structural Engineering and Mechanics
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• v.33 no.1
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• pp.1-14
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• 2009

Hong Kong is now recognized as an area of moderate seismic hazard, but most of the buildings have been designed with no seismic provision. It is of great significance to develop effective and practical measures to retrofit existing buildings against moderate seismic attacks. Researches show that beam-column joints are critical structural elements to be retrofitted for seismic resistance for reinforced concrete frame structures. This paper explores the possibility of using a Hydraulic Displacement Amplification Damping System (HDADS), which can be easily installed at the exterior of beam-column joints, to prevent structural damage against moderate seismic attacks. A series of shaking table tests were carried out with a 1/3 prototype steel frame have been carried out to assess the performance of the HDADS. A Numerical model representing the HDADS is developed. It is also used in numerical simulation of the shaking table tests. The numerical model of the HDADS and the numerical simulation of the shaking table tests are verified by experimental results.

• Structural Engineering and Mechanics
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• v.50 no.4
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• pp.419-439
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• 2014

In this study, the structural performance of a seven span masonry arch bridge was evaluated. Investigations were performed on Aspendos (Belkis) Masonry Arch Bridge which was located on road of Aspendos Acropolis City in Antalya, Turkey. The old bridge was constructed in the early of fourth century AD, but it was exposed to the earthquakes in this region and the overloading by the river water. The old bridge was severely damaged and collapsed by probably an earthquake many years ago and a new bridge was then reconstructed on the remains of this old bridge by Seljuk in the 13th century. The bridge has also been affected from overflowing especially in the spring of each year, so some protective measures should be taken for this monumental bridge. Therefore, the structural performance under these loading has to be known. For this purpose, an initial finite element model was developed for the bridge and it was calibrated according to ambient vibration test results. After that, it was analyzed for different load cases such as dead, live, earthquake and overflow. Three load combinations were taken into account by deriving from these load cases. The displacements and the stresses for these combination cases were attained and compared with each other. The structural performance of Aspendos Masonry Arch Bridge was determined by considering the demand-capacity ratio for the tensile stress of the mortar used in Aspendos Masonry Arch Bridge. After these investigations, some concluding remarks and offers were presented at the end of this study.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.291-300
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• 1998

This paper demonstrates how ambient vibration measurements at a limited number of locations can be effectively utilized to estimate parameters of a finite element model of a large-scale structural system involving a large number of elements. System identification using ambient vibration measurements presents a challenge requiring the use of special identification techniques, which ran deal with very small magnitudes of ambient vibration contaminated by noise without the knowledge of input farces. In the present study, the modal parameters such as natural frequencies, damping ratios, and mode shapes of the structural system were estimated by means of appropriate system identification techniques including the random decrement method. Moreover, estimation of parameters such as the stiffness matrix of the finite element model from the system response measured by a limited number of sensors is another challenge. In this study, the system stiffness matrix was estimated by using the quadratic optimization involving the computed and measured modal strain energy of the system, with the aid of a sensitivity relationship between each element stiffness and the modal parameters established by the second order inverse modal perturbation theory. The finite element models thus identified represent the actual structural system very well, as their calculated dynamic characteristics satisfactorily matched the observed ones from the ambient vibration test performed on a large-scale structural system subjected primarily to ambient wind excitations. The dynamic models identified by this study will be used for design of an active mass damper system to be installed on this structure fer suppressing its wind vibration.