• Steel and Composite Structures
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• v.22 no.2
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• pp.449-472
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• 2016

This paper studies the seismic behavior of reinforced concrete (RC) walls with encased cold-formed and thin-walled (CFTW) steel truss, which can be used as an alternative to the conventional RC walls or steel reinforced concrete (SRC) composite walls for high-rise buildings in high seismic regions. Seven one-fourth scaled RC wall specimens with encased CFTW steel truss were designed, manufactured and tested to failure under reversed cyclic lateral load and constant axial load. The test parameters were the axial load ratio, configuration and volumetric steel ratio of encased web brace. The behaviors of the test specimens, including damage formation, failure mode, hysteretic curves, stiffness degradation, ductility and energy dissipation, were examined. Test results indicate that the encased web braces can effectively improve the ductility and energy dissipation capacity of RC walls. The steel angles are more suitable to be used as the web brace than the latticed batten plates in enhancing the ductility and energy dissipation. Higher axial load ratio is beneficial to lateral load capacity, but can result in reduced ductility and energy dissipation capacity. A volumetric ratio about 0.25% of encased web brace is believed cost-effective in ensuring satisfactory seismic performance of RC walls. The axial load ratio should not exceed the maximum level, about 0.20 for the nominal value or about 0.50 for the design value. Numerical analyses were performed to predict the backbone curves of the specimens and calculation formula from the Chinese Code for Design of Composite Structures was used to predict the maximum lateral load capacity. The comparison shows good agreement between the test and predicted results.

• Journal of Powder Materials
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• v.20 no.5
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• pp.350-354
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• 2013

In this study, porous titanium samples were manufactured by space holder methods using two kinds of urea and sodium chloride space holders. Three-dimensional pore structures were obtained by a computed-tomography (CT) technique and utilized for finite element analysis in order to investigate the mechanical properties. The CT-based finite element analyses were in better agreement with the experimental results than unit cell model-based analyses. Both the experimental and CT-based results showed the same tendency that the elastic modulus decreased with increasing the porosities. The total porosity of the bulk body plays a key role in determining the elastic modulus of porous materials.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.71-78
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• 2004

Dedicated Short Range Communications(DSRC) as a prominent communications candidate for Intelligent Transportation Systems(ITS) have been developed to support ITS applications such as value-added information service, e-commerce, electronic toll payment, etc. These various applications associated with electronic payment through unsecure communication channel of DSRC suffer from security threats. To ensure secure payment, we have adopted appropriate cryptographic mechanisms including encipherment, authentication exchange and digital signature. The cryptographic mechanisms require to use cryptographic keys established between two communication entities. In this paper, we propose a secure electronic payment system which is designed to have some functions for strong authentication, encryption, key agreement, etc. Especially, we adopt domestic developed cryptographic algorithms such as EC-KCDSA and SEED for digital signature and block cipher, respectively. We can show those mechanisms are appropriate for the secure electronic payment system for ITS services under the DSRC wireless environment in aspects of constrained computational resource use and processing speed.

• The Journal of the Korea Contents Association
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• v.7 no.7
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• pp.171-178
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• 2007

In this paper the Partnership's Influence on the Success of IT-Outsourcing is studied. Especially the role of "Partnership" as Intermediate is mainly researched. As the result we can see the fact that the economic factor does not affect the Partnership and the success of IT-Outsourcing, because the IT-Outsourcing can cause sometimes the increase of the cost. On the other hand strategic factor and technical factor affect directly the Success of IT-Outsourcing. This means that the Success of IT-Outsourcing depends on the close cooperation between customer and service provider, rather than on the following the contents of the Service Level Agreement(SLA). In consequences the Partnership based on the steady and fluent communication and the feeling of sharing the risk and benefit between two parties is the key factor for the Success of IT-Outsourcing.

• Journal of Korea Multimedia Society
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• v.10 no.7
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• pp.902-911
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• 2007

GSM platform is a hugely successful wireless technology and an unprecedented story of global achievement. In less than ten years since the first GSM network was commercially launched, it became the world's leading and fastest growing mobile standard, using over 1 billion GSM subscribers across more than 200 countries of the world. GSM platform evolved into 3th generation mobile communication which includes not only voice call services but also the international roaming and various kinds of the multimedia services. GSM is an essential element techniques a safe data transmission and a personal private protection while support services. However, a crypto algorithm and a secure protocol for a safe data communication using GSM are indicating various kinds of problems. In this paper, we propose a more safer and more efficient authentication protocol in 3th generation network through analysis of GSM security mechanism of 2th/2.5th generation. This security protocol offers enforced security efficiency by using user verification between SIM/ME and reduction of authentication and key agreement step between SIM/ME/AuC.

• Journal of Nutrition and Health
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• v.38 no.9
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• pp.750-755
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• 2005

Hepcidin, a peptide hormone synthesized mainly by the liver, has been implicated as a key regulator of iron homeostasis. Results from studies with experimental animal models suggested that hepcidin levels are related with body iron status, but little data is available in human subjects. This study was conducted to determine the relationship between serum pro-hepcidin levels, blood indexes of anemia, and dietary iron intake in female college students. Serum pro-hepcidin concentrations were measured by enzyme-linked immunosorbent assay in eighty-two women with $22.1\pm0.2$ years old. Dietary intake data were collected by using the 24-hour recall method for 3 days. Mean concentrations of serum pro-hepcidin were 85.1 ng/ml$\pm$6.1(s.d.) with the range of 13.6-295.7 ng/ml. The median value of serum pro-hepcidin in the study subjects was 70.3 ng/ml. Serum pro-hepcidin concentrations were positively correlated with hemoglobin concentrations (r=0.273, p=0.013), and also with hematocrit (r=0.291, p=0.008). To examine whether the level of dietary iron intake affects serum pro-hepcidin levels, study subjects were divided into two groups according to the amounts of daily iron intake. Serum pro-hepcidin concentrations were $22\%$ lower in groups with low iron intake (${\leq}10.1$ mg/day), compared to high-iron intake group (>10.1 mg/day) . In conclusion, these data, as in agreement with findings in mice, suggest that hepcidin plays an important role in regulating iron metabolism in the human body.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.1
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• pp.49-60
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• 2002

Welding is essential in ship production since welding is very popular method for joining two or more metals. However, welding causes residual stress and distortion and these give a bad influence to the structure strength and assembly of ship blocks. Therefore, prediction and treatment of residual stress and distortion is a key to accuracy control in shipyard. In this paper, a computational procedure, based on thermal-elastic-plastic 3-dimensional FEA, has been suggested to simulate butt and fillet welding process. In the simulation process, temperature distribution at each time step is obtained by heat transfer analysis and then thermal deformation analysis is done with obtained temperature distributions to find the residual stress and distortion. In heat transfer analysis, enthalpy method is used to realize phase change at melting temperature. Also element birth and death method is used to simulate adding of weld metal in both heat transfer analysis and thermal elastic plastic analysis. The proposed procedure is verified by related researches and the results show good agreement with those of related researches.

• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.867-876
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• 2009

In this study, the stage-discharge relation curve made in 2006 is selected with standard curves to seize the hydraulic and geometric characteristics for the temporal variation of the river bed. The relationships among the standard stage-discharge relation curve and the existing stage-discharge relation curves, water level, cross sectional area, and flow velocity are analyzed. Jeokpogyo and Jindong which are the key station of Nakdong river are chosen for the study, with respect to the current river bed to convert the existing stage-discharge curves. The relationships for conversion of previous data, between water level and flow velocity are got. Also the relation equation between water level and cross sectional area and water level, flow velocity are derived. These conversion relationships shows good agreement between observed values and estimated values. It will be very useful to convert past hydraulic quantitations to current one.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.57-69
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• 2013

Progresses in ICT make the processing and exchange of personal data across international borders often necessary and relatively easy. The challenge lies in protecting fundamental rights and freedoms of individuals, notably the right to privacy and the right to personal information, while encouraging the free and secure flow of information across borders for the continued expansion of online transactions. The key to establishing a functioning international solution for personal data protection is to strike a right balance between the two camps which currently dominate the debate - the advocates of individual privacy rights on one side exemplified by the EU, and the proponents of self-regulation and economic efficiency on the other, represented by the U.S. In the face of a growing tension between the two sides each equipped with their own ideals, a practical solution may lie in utilizing established institutions of standardization such as ISO and IEC as a ground upon which an agreement can take its root.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.3
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• pp.289-296
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• 2009

Natural frequency is a key parameter to determine the seismic and wind loading of tall flexible structures, and to assess the wind-induced vibration for serviceability check. In this study, natural frequencies and associated mode shapes were obtained from measured acceleration data and system identification technique. Subsequently, finite element(FE) models for a tall reinforced concrete buildings were built using a popular PC-based finite element analysis program and calibrated to match their natural frequencies and mode shapes to actual values. The calibration of the FE model included: 1) compensation of modulus of elasticity considering the mix design strength, 2) flexural stiffness of floor slabs, and 3) major non-structural components such as plain concrete walls. Natural frequencies and mode shapes from the final FE model showed best agreement with the measured values.