• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.326-330
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• 2004

Thermosetting matrix composites have disadvantages in terms of moulding time, repairability and manufacturing cost. Thus the high-performance thermoplastic composites to eliminate such disadvantages have been developed so far. As a result of environmental and economical concerns, there is a growing interest in the use of thermoplastic composites. However, since their mechanical properties are very sensitive to the environment such as moisture, temperature etc., those behaviors need to be studied. Particularly the temperature is a very important factor influencing the mechanical behavior of thermoplastic composites. The effect of temperature have not yet been fully quantified. Since engineering applications of reinforced composites necessitate their fracture mechanics characterization, work is in progress to investigate the fracture and related failure behavior. An approach which predicts the tensile strength was perpormed in the tensile test. The main goal of this work is to study the effect of temperature on the result of tensile test with respect to GF/PE composite. The tensile strength and failure mechanisms of GF/PE composites were investigated in the temperature range $60^{\circ}C\;to\;-50^{\circ}C$. The tensile strength increased as the fiber volume fraction ratio increased. The tensile strength showed the maximum at $-50^{\circ}C$, and it tended to decrease as the temperature increased from $-50^{\circ}C$. The major failure mechanisms was classified into the fiber matrix debonding, the fiber pull-out, the delamination and the matrix deformation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.133-140
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• 2003

The sandwich plate has been widely used as an efficient structural member because it has high strength-to-weight and high stiffness-to-weight ratios. To properly design the aluminum extrusion plate , it is necessary to analyze structural behaviors of the extrusions, however, the aluminum extrusions have been rarely studied until now. In the optimization process through numerous iterative calculations, finite element analysis of the sandwich plate with hollow core section requires a considerable amount of computation time and cost. In this paper, the aluminum extrusion plate with truss-core is transformed into an equivalent homogeneous orthotropic plate with appropriate elastic constants. The procedure to evaluate accurate equivalent elastic constants is also established. Using these elastic constants, simple theoretical formulas of the stresses and deflection are proposed in case of the simply-supported orthotropic thick plate under uniform pressure. Through the comparison with the results by commercial FEM code(ANSYS), it is verified that the proposed simpified formula has a good efficiency and accuracy.

• Steel and Composite Structures
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• v.20 no.4
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• pp.801-812
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• 2016

In an actual design, none of the structures with shear behaviors will be designed for torsional moments. Any failure or damages to roofs, infills, shear walls, and braces caused by an earthquake, will inevitably result in relocation of center of mass and rigidity of the structure. With these changes, the dynamic characteristics of structure could be changed during an earthquake at any moment. The main objective of this paper is to obtain the relationship between time-varying eccentricity of load and corner lateral displacement. In this study, various methods have been used to determine the structural response for time-varying lateral corner displacement. As will be seen below, some of the structural calculation methods result in a significant deviation from the actual results, although these methods include the interaction effects of modes. Controlling the lateral displacement of structure can be performed in different ways such as, passive dampers, friction dampers, semi-active systems including the MR damper and active Systems. Selecting and locating these control systems is very important to bring the maximum safety with minimum cost into the structure. According to this study will be show the relation between the corner lateral displacements of structure and time-varying eccentricity by different kind of methods during an earthquake. This study will show that the response of the structure at the corners due to an earthquake can be very destructive and because of changing the eccentricity of load, calculating the maximum possible response of system can be carried out by this method. Finally, some kind of systems must be used for controlling these displacements. The results shows that, the CQC, DSC and exact methods is comply each other but the results of Vanmark method is not comfortable for these kind of buildings.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.5-16
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• 2015

In the long span bridge construction, construction cost portion of large scale marine foundation is about 40% (KICTEP, 2007). In this study, designs for deep water depth large composite foundation of a super long span cable-stayed girder bridge of prototype were performed by three design methods (ASD, LRFD, Eurocode) and the behaviors of a large diameter drilled shaft were analyzed and the 3D numerical analysis was performed. As a result, the soft rock socket lengths in allowable stress design estimation method were the longest. The soft rock socket lengths estimated by the design approach 2 among Eurocode and the LRFD were similar. The longer the socket length socketed in the soft rock was, the smaller the axial force acting on a large-diameter drilled shaft head was and the smaller the settlement of drilled shaft was.

• The Research Journal of the Costume Culture
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• v.28 no.4
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• pp.446-462
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• 2020

The objectives of this study are to explore the information source, assessment, and preferred styles of 3D virtual influencers(VI), to investigate the expected impact of advertisements with 3D VIs on brands, and to explore ways of expanding the use of 3D VIs. In-depth interviews with 40 males and females in their 20s and 30s were conducted and qualitative data were analyzed. The study results are summarized as follows. First, the information source of the 3D VI was SNS, acquaintances, and broadcasting. Second, 3D VIs were considered positively due to their attractive appearance, wide utilization, innovative use, freshness, separation from private identity, and time and cost savings, while considered negatively due to their unrealistic appearance and antipathy against replacing a person's role. Third, the preferred appearance styles of the 3D VI differed according to the level of virtuality although the majority of interviewees preferred similar looks to real people with low virtuality. Fourth, diverse image qualities such as innovative, differentiated, trendy, high-value, professional, and future-oriented were considered as transferred to the brand advertised by 3D VIs. Fifth, advertisements with 3D VIs may help build positive perceptions of advertised brands that may lead to purchase behaviors for some consumers. Lastly, to expand the use of 3D VIs, the specific advantages of virtual models should be maximized with consideration of how to implement a variety of body types and images of models. Findings present an important foundation to generate strategies to better apply 3D VIs to the fashion market.

• Journal of the Korean Society for Heat Treatment
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• v.30 no.6
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• pp.264-270
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• 2017

In this study, while the abrasive plates for diamond have been prepared through mechanical alloying and sintering of elemental powders, a fabrication route of plasma thermal coatings has been adopted for the first time. When diamond knife is sharped or polished, a metal plate has been applied, which is made of mechanical alloying and sintering. In this study, in order to develop a cost - effective manufacturing process, plasma coatings of FeCrNi and Ti on cast iron plate were applied together with Al intermediate layer coatings. The plasma coatings were successfully performed, and the optimum coating layer conditions were discussed in terms of micro-structural observations at the interfaces.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.1
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• pp.43-49
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• 2005

The package used to transport radioactive materials, which is called by the shipping cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than the one for test, the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors, the results depend on how users apply the codes and can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique lot the free drop impact test of the cask and investigated several vulnerable cases. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.29-38
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• 2015

In this study, track dynamic interaction characteristics caused by the vehicle running through transitional section such as bridge abutments were studied using the finite element analysis program. The geometric condition of track was generated by trigonometric function and allowable maximum track irregularity is determined by KORAIL track maintenance criteria. The sub-infrastructure under rail fastener system was modelled by 3D solid elements. To reduce computational cost only half track line is numerically considered and the roller boundary condition was applied to each side of model. In this study, the vehicle-track dynamic interaction analysis was carried out for standard Korean transition section of concrete track and the dynamic behaviors were investigated. The dynamic characteristics considered are wheel load variation, vertical acceleration at body, and maximum Mises stress at each part of transitional section.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.311-314
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• 2008

While relevant fields of construction industry have rapidly changed, the adaptation (skill) level of individuals to apply or utilize them has slowly followed. By understanding how individuals resist and conform under this change of construction industry and which factors are important for the adaptation, much time, effort, and cost can be saved for organization operation and management, and these saved resources will be able to be effectively invested to others. Accordingly, for construction industry it is necessary to understand and study how the users fit into the rapid technological change. Through this research, therefore, a systematic guideline should be created for the relevant fields of construction industry. For this research, the characteristics of individual personalities and behaviors based on the traditional model was observed and factors that contribute to the resistance and their mutual relations were theoretically identified and categorized, and then a conceptual and figurative model to show the mutual relation between the identified resistive factors was suggested.

• The Journal of Korean Medical History
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• v.24 no.1
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• pp.9-15
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• 2011

Recently, the oriental medicine industry in Korea has faced much hardship, due to the decreasing number of patients. Therefore, it is essential to investigate the reasons why patients are avoiding oriental medicine, because the percentage of people consuming medical service is an important marker that assesses the value of medical service. The researcher(s), based on theories on factors that affect health, health behaviors, and diseases, sought to find reasons why oriental medicine clinics saw a decline in the number of patients. Also, by proposing the problems inside the oriental medicine, I came to the following conclusion. -Because Koreans have low expectations for oriental medicine, they do not consider it as full medical service. Also, when they get sick, they are reluctant to seek oriental medicine because of reasons such as the limits of oriental medicine and check-ups, expensive medical cost, negative perception of oriental medicine, not enough support from the media, the old image of the oriental medicine and the little power the industry has on the society. -Among the inner problems of the oriental medicine community was the limitations that the science face on incurable and chronic diseases in terms of treatment and management, little professionalism, lack of scientific evidence, the attitude of the oriental medicine society, lack of sophistication in research methodology, and limitations in responding to changes in public health and the surroundings. The purpose of medicine is to eliminate the possibility of shortened life and dangers by treatment of diseases and health maintenance. For this to happen, structural and developed medical theories and means of treatment are necessary. The researcher hypothesizes that the problems that the oriental medicine society is facing mainly come from the lack of efforts and ability to provide such necessities.