• Structural Engineering and Mechanics
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• v.72 no.1
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• pp.31-41
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• 2019

Structural integrity assessment of piping components is of paramount important for remaining life prediction, residual strength evaluation and for in-service inspection planning. For accurate prediction of these, a reliable fracture parameter is essential. One of the fracture parameters is stress intensity factor (SIF), which is generally preferred for high strength materials, can be evaluated by using linear elastic fracture mechanics principles. To employ available analytical and numerical procedures for fracture analysis of piping components, it takes considerable amount of time and effort. In view of this, an alternative approach to analytical and finite element analysis, a model based on relevance vector machine (RVM) is developed to predict SIF of part through crack of a piping component under fatigue loading. RVM is based on probabilistic approach and regression and it is established based on Bayesian formulation of a linear model with an appropriate prior that results in a sparse representation. Model for SIF prediction is developed by using MATLAB software wherein 70% of the data has been used for the development of RVM model and rest of the data is used for validation. The predicted SIF is found to be in good agreement with the corresponding analytical solution, and can be used for damage tolerant analysis of structural components.

• Geomechanics and Engineering
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• v.19 no.3
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• pp.283-293
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• 2019

Evaluating the stability of the excavation face of the cross-river shield tunnel with good accuracy is considered as a nonlinear and multivariable complex issue. Understanding the stability evaluation method of the shield tunnel excavation face is vital to operate and control the shield machine during shield tunneling. Considering the instability mechanism of the excavation face of the cross-river shield and the characteristics of this engineering, seven evaluation indexes of the stability of the excavation face were selected, i.e., the over-span ratio, buried depth of the tunnel, groundwater condition, soil permeability, internal friction angle, soil cohesion and advancing speed. The weight of each evaluation index was obtained by using the analytic hierarchy process and the entropy weight method. The evaluation model of the cross-river shield construction excavation face stability is established based on the idea point method. The feasibility of the evaluation model was verified by the engineering application in a cross-river shield tunnel project in China. Results obtained via the evaluation model are in good agreement with the actual construction situation. The proposed evaluation method is demonstrated as a promising and innovative method for the stability evaluation and safety construction of the cross-river shield tunnel engineerings.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.5
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• pp.347-354
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• 2023

In this study, virtual reality software was developed to support the generation of an analysis model of a Hanok and to increase the use of the completed analysis model. The structural analysis model of the Hanok was generated using midas Gen, a general-purpose structural analysis software. After converting it into a text-based input file, the developed software stores the data necessary for the examination of the analysis model. Then, in the developed virtual reality software, the three-dimensional analysis model of the Hanok can be visualized in various ways and the related data can be shown by selecting a specific member. Through this process, errors in the analysis model can be identified and corrected to build a complete analysis model. The developed software was applied to three Hanok cases to verify its applicability and effectiveness. The software is expected to be used in other fields besides the structural field.

• Women's Health Nursing
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• v.7 no.2
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• pp.141-156
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• 2001

The purpose of this study was to develop and test the structural model of a contraceptive behavior in Married Korean women. A hypothesis model was constructed on the basis of the health belief model, the theory of planned behavior and extensive literature review of contraception. The model was built by seven constructs. Four exogeneous variables included in the model were consisted of the contraceptive knowledges, the perceived threats, the sexual autonomy and the communication within a couple. Four endogenous variables were consisted of the attitudes toward contraception, the perceived control, the ability to plan a intercourse and the contraceptive behaviors. Empirical data for testing the hypothetical model were collected by the self report questionnaires from 243 Korean married women. The questionnaires used in this study were developed by this researcher and their Cronbach's alpha scores were ranged from .60 to .88. The collected data were analyzed by SPSS program(ver. 8.0) for descriptive statistical analysis and LISREL program(ver. 8.12a) for covariance structural analysis. On the basis of this results, it could be suggested that contraceptive behaviors be greatly affected by the perceived threats, the communications within couple, the attitudes toward contraception and the perceived control. Finally this model would be useful for the practice, theory and research of nursing.

• Journal of the Korea Convergence Society
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• v.5 no.3
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• pp.17-22
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• 2014

The stress between work piece and end mill at the use of end mill at machining and the structural deformation due to the and the pressure are investigated by simulation analysis of three end mill models in this study. These results are achieved with structural and fatigue analyses. Model 1 has the deformation less than model 2 or model 3. As the maximum equivalent stress of model 1 is shown to become the least among all models, model 1 can endure the highest load by comparing with other models. It is useful to estimate the damage prevention and the durability by applying this study result into the design of end mill.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.12
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• pp.830-842
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• 2015

This paper aims to develop a SI(structural identification) technique using the kinetic energy optimization technique(KEOT) and the direct matrix updating method(DMUM) to decide on optimal location of sensors and to update FE model respectively, which ultimately contributes to a composition of more effective SHM. Owing to the characteristic structural flexing behavior of cable bridges, which makes them vulnerable to any vibration, systematic and continuous structural health monitoring (SHM) is pivotal for them. Since it is necessary to select optimal measurement locations with the fewest possible measurements and also to accurately assess the structural state of a bridge for the development of an effective SHM, a SI technique is as much important to accurately determine the modal parameters of the current structure based on the data optimally obtained. In this study, the KEOT was utilized to determine the optimal measurement locations, while the DMUM was utilized for FE model updating. As a result of experiment, the required number of measurement locations derived from KEOT based on the target mode was reduced by approximately 80 % compared to the initial number of measurement locations. Moreover, compared to the eigenvalue of the modal experiment, an improved FE model with a margin of error of less than 1 % was derived from DMUM. Finally, the SI technique for long-span bridges proposed in this study, which utilizes both KEOT and DMUM, is proven effective in minimizing the number of sensors while accurately determining the structural dynamic characteristics.

• Journal of Families and Better Life
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• v.24 no.1 s.79
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• pp.11-30
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• 2006

The purpose of this study was to verify a Structural Equation Model that constructed the causations among the leisure constraints, leisure. motivation, and leisure participation. This model posits that constraints determine motivation to participation. Concretely, structural and interpersonal leisure constraints(contextual factors) will affect interpersonal leisure constraints in the light of ecological perspective. Also, leisure constraints will affect leisure motivation based on self-determination theory that may influence leisure participation indirectly. A survey questionnaire was administered to 301 elderly in an institution for the elderly. A measurement model and a structural equation model estimates by Maximum Likelihood method(ML method) utilizing LISREL 8.0 ver. The analysis showed that a goodness of fit is good of structural equation model presented in the study. And, all hypothesis adopted about causations among the leisure constraints, leisure motivation, leisure participation.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.160-167
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• 1993

In earthquake structural engineering towards a better understanding of both the earthquake ground motion and structural response, the design of concrete structures to resist strong ground input motions is not a simple matter, and analytical models for such structures must be developed from a design perspective that accounts for the complexities of the structural responses. The primary objective earthquake structural engineering research is to ensure the safety of structures by understanding and improving a design menthodology. Ideally, this would require the development of an analytical model related to a design methodology that ensures a dectile performance. For the accurate assessment of the adequacy of analytically developed model, experiments conducted to study the inplane inelastic cyclic behavior of structures should verify the analytical approach. The paper is to demonstrate experimentally verified analytical method that provide the adequate degree of safety and confidience in the behavior of R.C. structural components and further attempts to extend the developed modeling technique for use by practicing structural engineers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.04a
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• pp.50-55
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• 1991

This paper presents database technique for an computer-integrated structural design system of buildings. Network database designed to support all the processes of structural design, such as, planning, modelling, analysis, member design and redesign processes etc. stores all information from user input and system results effectively and so provides centeral communication area between applications. The user interface wi th interactive and batch modes plays roles of building modeler including conventional pre-processor and post-processor. The concepts of 'Planar Surface Modeling' and 'Geometry Zoning' are defined for easy construction of building model. The concept presented in this paper will save the time and memory required for model generation and contribute to data consistency, thus leave a designer more time actually performing the analyses and interpreting the results. The formulation of automating the process of bulilding model ins and structural analysis is the key to study.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.19-23
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• 2002

A reliability-based cost-benefit model for the risk management of oil platforms in the formulation of optimal decisions based on life-cycle consideration is proposed. The model is based on structural risk assessments and the integration of social issues and economics into the management decision process. Structural risks result from the platform's exposure to the random environmental loading associated with the offshore site where it is located. Several alternative designs of a typical platform are proposed and assessed from the cost-effectiveness viewpoint. This assessment is performed through the generation of cost/benefit relationships that are used, later on, to select the optimal design.