• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.49-52
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• 2007

Recently, as architectural concrete structures become high-rise and megastructured, concrete become high-strengthened and, by ensuring products of more stability, air compression and rationalization of construction are required. In general, product management test of precast concrete member, specimen for management cured in the same condition with precast concrete member is substitutively used for strength test. However, large cross-sectional precast concrete members such as columns show large temperature increase in manufacturing process not only by external heating but also by concrete itself's hydration heating. Therefore, it is expected that specimen for management to predict strength and compression strength of precast concrete member shows different temperature history and strength characteristics. Concerning this, in order to suggest temperature history and strength characteristics of high strength mass concrete suitable for precast concrete application, this study comprises the inclusive investigations on the relations between management specimen with similar temperature history and core strength, and the strength characteristics per member cross-section dimensional value and per water-bonding material ratio value.

• YAKHAK HOEJI
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• v.59 no.2
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• pp.66-69
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• 2015

A concise synthesis of flurbiprofen, a member of the non-steroidal anti-inflammatory 2-arylpropionic acids, has been accomplished. The key feature of this synthesis involves successive palladium-catalyzed cross coupling reactions. In particular, a 2-arylacylate intermediate, which easily converted to the key 2-arylpropionic acid scaffold, was afforded by a versatile palladium-catalyzed cross coupling reaction between diazopropanate and bisphenylboronic acid. This synthetic procedure would facilitate synthesis of the flurbiprofen and anti-inflammatory 2-arylpropionic acid derivatives.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.143-155
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• 2001

Generally, truss design has been determined by the designer's experience and intuition. But if we perform the most economical structural design we must consider not only cross-sections of members but also configurations(howe, warren and pratt types etc.) of single truss as the number of panel and truss height. The purpose of this study is to develope automated optimum design techniques for steel truss structures considering cross-sections of members and shape of trusses simultaneously. As the results, it could be possible to find easily the optimum solutions subject to design conditions at the preliminary structural design stage of the steel truss structures. In this study, the objective function is expressed as the whole member weight of trusses, and the applied constraints are as stresses, slenderness ratio, local buckling, deflection, member cross-sectional dimensions and truss height etc. The automated optimum design algorithm of this study is divided into three-level procedures. The first level on member cross-sectional optimization is performed by the sequential unconstrained minimization technique(SUMT) using dynamic programming method. And the second level about truss height optimization is applied for obtaining the optimum truss height by three-equal interval search method. The last level of optimization is applied for obtaining the optimum panel number of truss by integer programming method. The algorithm of multi-level optimization programming technique proposed in this study is more helpful for the economical design of plane trusses as well as space trusses.

• Steel and Composite Structures
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• v.25 no.5
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• pp.625-638
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• 2017

This paper presents a novel approach that describes the first-order (linear elastic) partial interaction analysis of members formed by multi-components based on the Generalised Beam Theory (GBT). The novelty relies on its ability to accurately model the partial interaction between the different components forming the cross-section in both longitudinal and transverse directions as well as to consider the cross-sectional deformability. The GBT deformations modes, that consist of the conventional, extensional and shear modes, are determined from the dynamic analyses of the cross-section represented by a planar frame. The partial interaction is specified at each connection interface between two adjacent elements by means of a shear deformable spring distributed along the length of the member. The ease of use of the model is outlined by an application performed on a multi-component member subjected to an eccentric load. The values calculated with an ABAQUS finite element model are used to validate the proposed method. The results of the numerical applications outline the influence of specifying different rigidities for the interface shear connection and in using different order of polynomials for the shape functions specified in the finite element cross-section analysis.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.215-222
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• 2004

Drift design methods using resizing techniques have been presented as a practical drift control methods of high-rise buildings. Most drift design methods using the resizing techniques have adopted the cross-sectional area as the design variables for all structural members in a structure. However, the cross-sectional area is not always governing sectional property for the structural members, but the governing sectional property of each member is dependent on the characteristics of member forces. In this paper, a drift design method using the sectional property related to the governing displacement participation factor as the design variable of each member is presented and applied to the drift design of 20-story steel frame-shear wall system. It can be noted from example test that drift design method considering member characteristics shows similar or somewhat better results in the view point of structural weights and the accuracy of displacement estimation.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.249-259
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• 2011

In this study, the distortional behaviors of tub-section steel girders subjected to torsional loading were analyzed, and predictor equations were developed for estimating the member forces induced in the internal bracing system installed in the steel tub girders. Torsional loadings originated either by eccentric vertical loading or girder curvature were decomposed into the pure torsional force component that does not affect the distortional box deformation, and into the distortional force component that directly induces box distortion. The axial member forces induced in the internal cross frames were formulated as a function of the magnitude of torsional loading through the analytical investigation of the interactions between the distortional force component and internal cross frames. To verify the proposed equations, three-dimensional finite element analysis (3D FEA) was conducted for the straight simple-span girder and the three-span continuous girder samples. Very good agreement was found between the member forces from the FEA and the proposed equations.

• Korean Journal of Health Education and Promotion
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• v.33 no.2
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• pp.47-55
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• 2016

Objectives: We investigated whether the rate of depressive symptom is higher among family members of asthmatic patient compared to people who had no asthmatic family member. Methods: This study used data from the fourth and fifth Korea National Health and Nutrition Examination Survey (2007-2012). In this cross-sectional study, 15,987 men (mean age 46.4) and 20,906 women (mean age 47.4) were included. To compare the rate of depressive symptoms in individuals who had a family member with asthma and those who did not have, we analyzed data using survey logistic regression. Results: Diagnosed depression was reported by 3.0% of the study population, by 4.2% of asthmatic patient's family member, and by 3.0% of individuals who did not have a family member with asthma. Family members of asthmatic patient increased odds of diagnosed depression compared with those who did not had an asthmatic family member (odds ratio = 1.56, p = 0.008). Conclusions: To prevent depression among family members of asthmatic patient, health education for entire family of asthmatic patient need to be considered. Also, government and policy makers should give more attention to caregivers who had a family member with asthma.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.49-63
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• 2015

In this paper, the results of evaluation on the member forces in the virtual subsea tunnel lining segments and optimal thickness of the segment with changes in depth were presented. To evaluate member forces on the hypothetical subsea tunnelling cases were developed and the segmental lining member forces were calculated by performing structural analysis using the 2-Ring Beam model. Through a preliminary reinforcement design review of the cross-section using calculated member force, optimal reinforcement design was selected. Based on the results, the variations of member forces with construction conditions such as the cover depth and the hydraulic pressure are presented. In addition, optimum segment lining designs were developed for various tunnelling conditions.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.46_47
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• 2009

The West African Power Pool is currently developing the regional electricity market for its member states. As the basic design for the cross-border power trading system for the West African Power Pool, the step-by-step evolution, the Baseline System and the Fullscale System, is estimated. Along with the interconnection project between member countries, the various functions from the data acquisition and processing by the Baseline System to the interchange trading by the Fullscale System will be implemented gradually.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.214-218
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• 2011

In order to survive in turbulent and competitive markets, automotive part manufacturers try efforts to develop new manufacturing technologies for ultra-lightweight, high-intensity and environmentally-friendly parts. Most of front lower arm is manufactured by welding process between upper- and lower panel which are produced by press stamping process. Because lower arm mounted on the cross member parts is one of the important complementary parts. So, to improve safety and lightweight of these parts, hybrid technologies are used in this paper. As hybrid technologies are applied to be front sub-frame, rear cross member and other chassis parts as well as front lower arm, the 20% lightweight has been achieved compared with existing steel parts.