• Transactions of Materials Processing
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• v.21 no.3
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• pp.186-194
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• 2012

Hot stamping is a forming method that offers various advantages such as superior mechanical properties, good formability, and very small springback. However, relatively large-sized parts, such as front pillars, exhibit poor formability when hot stamped due to the limited material flow and thickness reduction imparted by the process. This reduction in thickness can also lead to cracks. One of the reasons is the relatively high friction between the sheet and the die. In this study, in order to obtain the optimal conditions for hot stamping of front pillars, various process parameters were studied and analyzed using the sheet forming software, J-STAMP. The effects of various parameters such as the die structure, blank shape, blank holding force, punch speed, clearance(upper and lower dies) and distance block were analyzed and compared.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.773-783
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• 2016

Both coordinated multi-point transmission and frequency reuse are effective approaches to mitigate inter-cell interference and improve network coverage. The motivation of this work is to explore the manner to effectively utilize the spectrum resource by reasonably combining cooperation and frequency reuse. The $Mat{\acute{e}}rn$ cluster process, which is appropriate to model networks with hot spots, is used to model the spatial distribution of base stations. Two cooperative mechanisms, coherent and non-coherent joint transmission (JT), are analyzed and compared. We also evaluate the effect of multiple antennas and imperfect channel state information. The simulation reveals that the proposed approach to combine cooperation and frequency reuse is effective to improve the network coverage for users located at both the center and the boundary of the cooperative region.

• Journal of architectural history
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• v.6 no.3 s.13
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• pp.9-22
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• 1997

The Wooden Stupa of Hwangnyongsa Temple, existed from Shilla to Koryo Dynasty, is recognized as a typical model of the Korean wooden stupa. The related records on this stupa are found in some historical documents including The Chronicles of the Three States ${\ulcorner}$三國史記${\lrcorner}$. This study, through the interpretation of these documents, attempts to discuss and analyse design and structural methods of the stupa, viz., i) the relationship with both Chinese and Japanese wooden stupa, ii) the height, iii) each floor's linking methods, iv) the 'Noban' (Basement of the upper part), v) structure of the 'Simju' (Central pillar) and vi) the stairs and the handrails. The results of this study would be hopefully used for the further researches as well as the restoration of this precious architectural asset.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.10
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• pp.901-906
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• 2007

Lightweight body due to the decrease of panel thickness and reinforcing member might cause low stiffness. On the other hand, high stiffness body requires an increase of mass. Front pillar section area has been decreased for increasing the driver's visual field. Global vehicle stiffness is affected by stiffness distribution ratio between upper part and lower part at a side body structure. This paper describes a process used to evaluate the stiffness distribution ratio based on strain energy. In addition, optimum design schemes are presented for high stiffness and lightweight body structure considering the investigated stiffness distribution ratio.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1518-1525
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• 2008

This paper concerns optimum design of 2-Arch tunnel. A 2-Arch tunnel adopted in a subway tunnel construction site is considered in this study. A calibrated 3D finite element model was adopted to conduct a parametric study on the lagged distance between left and right tunnel faces. The results of analysis were examined to determine optimum lagged distance for minimizing the interaction between the left and right tunnels. The results indicated that the shotcrete lining stress and the center pillar load are more influenced by the second tunnel excavation than the tunnel deformation. Also shown is that a lagged distance of 20m is sufficient to minimize the interaction between two tunnels. Fundamental mechanism of 2-arch tunnel was also investigated based on the results.

• Korean Institute of Interior Design Journal
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• no.22
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• pp.85-91
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• 2000

The purpose of this study is to grasp the element and method of traditional expression appeared in hotel lobby spaces, and present the direction of traditional expression applicable to the domestic hotel lobby space. Therefore, this study analyzed traditional expression according to its element and method taken out from the prior researches related to it. Specifically, the element of traditional expressions divided into the element of space organization, the element of structure (bottom, wall, ceiling, window, door and pillar), and the element of decorative design(furniture, illumination, artistic ornament, color, and material). The method of traditional expressions divided into the method of prototype reappearance, prototype transformation, reinterpretation, and abstract. The target of analysis has been 27 hotels designed since 1970s. and described as expressed traditionality in architecture-technical journals and books in the inside and outside of the country. considering these results, it seems that the traditional expressions using more various elements and more various element and methods have to used in domestic hotels. Specifically, when expressing traditionality in the lobby space of domestic hotel, it is important to decided the method expressing traditionality at first, and the traditional expressions using the element of space organization, structure, decorative design, and so based on the method expression traditionality was fulfilled with coordination.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.526-531
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• 2011

A dash panel component, close to passengers, plays a very important role to protect heat and noise from a power train. Meanwhile, it is also a main path that transfers vibration energy and eventually radiates acoustic noise into the cavity. Therefore, it seems important to provide an optimal design scheme incorporating sound packages such as dash isolation pad and carpet, as well as structures. The present study is the extension of the previous investigation how design variables affect sound radiation, which was carried out using the simple plate and framed system. The system taken into account in this paper is a dash panel component of a sedan, which includes A pillar, front side member, dash panel and the corresponding sound packages. Design variables such as panel thickness and sound package layers are investigated how they are related for the better radiation performance (i.e. structure-borne) and sound transmission loss (i.e. air borne).

• Korean Journal of Social Welfare
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• v.62 no.2
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• pp.329-348
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• 2010

Following the welfare state typology well known, the typology in terms of individual system in welfare state has been widely examined and, pension which is the biggest and most important in welfare state has been classified into Beveridge and Bismarckian types based on their pension system design. Such typology focused on benefit type or size of private pension has been recently refined to add a new type - 'Bismarckian Lite' type - in addition to traditional Beveridge and Bismarckian types. Whereas the pension reforms in the developed countries has been changes within their pension regimes, the Korean pension reform in 2007 seems to have changed the existing social insurance type into the 'Bismarckian Lite' type. However, considering the immaturity of Korean pension regime, it is difficult to conclude the existing status of the Korean pension regime and, the Korean one can be classified into a multi-pillar one. Over the last decades the developed countries have increased the size of private pension regardless of their original pension regimes, which tends to converge into multi-pillar schemes. Accordingly, there is recently a new typology focused on the degree of regulation in terms of private pensions, which seems to be the better perspective. It will be more important how to regulate the (immature) occupational pension as well as the National Pension in Korea. Considering that old age income security in countries where the public regulation regarding private pension was absent has been deteriorated, it would be necessary to strengthen the role of government to effectively regulate private pension.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.2
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• pp.46-54
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• 1994

In this paper, an analysis and design method is proposed, which is to improve the directivity of microstrip array antennas conformed to a cylindrical surface. In the case of forming an arc-array in the circumferential direction on a circula-cylinder surface, the circular-cylinder can be approximated to a polygonal-pillar and on each pillar-planes the sub-arrays, Dolph-Tschebyscheff array and uniform array with a beam steered in the desired direction, would make a sharp directivity for the total cylin- drical array antenna. And the radiation pattern according to the type of its sub arrays is analyzed and compared using the cylindrical-cavity codel. A cylindrical microstrip array antenna, with 12 elements and uniform arra as a sub-array which have an equal distance$\lambda_0$/2between the elements, is manufactured and conformed to a cylinder with radius of 6 The measured data of side lobe level, HPBW and FNBW are - 13dB, $9^{\circ}$, and $15{\circ}$, ,respectively. This result shows a good improvement on the directivity comparing with a linear array.

• Earthquakes and Structures
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• v.3 no.6
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• pp.821-838
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• 2012

This paper proposes a new three-layer pillar-type hysteretic damper system for residential houses. The proposed vibration control system has braces, upper and lower frames and a damper unit including hysteretic dampers. The proposed vibration control system supplements the weaknesses of the previously proposed post-tensioning vibration control system in the damping efficiency and cumbersomeness of introducing a post-tension. The structural variables employed in the damper design are the stiffness ratio ${\kappa}$, the ductility ratio ${\mu}_a$, and the ratio ${\beta}$ of the damper's shear force to the maximum resistance. The hysteretic dampers are designed so that they exhibit the targeted damping capacity at a specified response amplitude. Element tests of hysteretic dampers are carried out to examine the mechanical property and to compare its restoring-force characteristic with that of the analytical model. Analytical studies using an equivalent linearization method and time-history response analysis are performed to investigate the damping performance of the proposed vibration control system. Free vibration tests using a full-scale model are conducted in order to verify the damping capacity and reliability of the proposed vibration control system. In this paper, the damping capacity of the proposed system is estimated by the logarithmic decrement method for the response amplitudes. The accuracy of the analytical models is evaluated through the comparison of the test results with those of analytical studies.