• Composites Research
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• v.20 no.3
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• pp.8-16
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• 2007

Bending collapse of light-weight square tubes used for vehicle structure components is a dominant failure mode in oblique collision and rollover of vehicles. In this paper bending performances of aluminum-GFRP hybrid tube beams were evaluated in relation with bending deformation behavior and energy absorption characteristics. Aluminum/GFRP hybrid tube beams fabricated by inserting adhesive film between prepreg and metal layer were used in the bending test. Failure mechanisms of hybrid tubes under a bending load were experimentally investigated to analyze the bending performance as a function of ply orientation and composite layer thickness. Ultimate bending moments and energy absorption capacity of hybrid tube beams were obtained from the measured load-displacement corves. It was found that aluminum/GFRP hybrid tubes could be converted to rather stable collapse mode showing excellent energy absorption capacity in comparison to the pure aluminum tube beams. In particular, the hybrid tube beam with $[0^{\circ}/90^{\circ}]s$ composite layer showed a large improvement by about 78% in energy absorption capacity and by 29% in specific energy absorption.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.525-525
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• 2005

This study is for the seismic analysis and the structural integrity evaluation of the box beam for supporting nuclear fuel-transfer-basket of the HANARO reactor pool. For performing the seismic analysis and evaluating the structural integrity in air or submerged condition, the finite element model of the fuel-transfer-basket and its supporting box beam(the coupled model) was developed. The hydrodynamic effect is also considered by using added mass concept. The seismic response spectrum analyses of the coupled model under the design floor response spectrum loads of Safe Shutdown Earthquake(SSE) were performed. Through the numerical experiments, the analysis results show that the stress values of the coupled model lot the structural integrity are within the ASME Code limits.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.133.1-133.1
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• 2005

• Korean Journal of Social Welfare
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• v.53
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• pp.285-310
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• 2003

As National Pension Scheme for all nation complete in 1999 through expanding application in cities, the public pension including Public Occupational Pension became main axis of old-age income maintenance. After 4years since then, now, it is only half of total National Pension insured persons who have been qualified to receive pension through participate and contribution. The other half of National Pension insured is left the excluded from public pension. This paper is intended to identify scale and characteristics of the excluded from public pension and to analysis its cause, and to explore policy measures for solving the excluded's problem. for current recipients over 60 years old generation, the its excluded's scale is no less than 86% of the old over 60 years. The probability of getting in the excluded is high in case of old elderly and female for current elderly generation. For future recipients 18-59 years working generation, the its excluded's scale is no less than 61% of the 18-59 years total population. The probability of getting in the excluded is high in case of 18-29 years and female for current working generation. As logistic regression analysis determinant factor of paying or not pension contribution for future recipients, it appear that probability of getting in the excluded for current working generation is high in case of younger old, lower education attainment, irregular employee, working at agriculture forestry fishery sector, construction sector, wholesale retail trade restaurants hotels sector, financial institution and insurance real estate renting and leasing sector in comparison with manufacturing sector, occpaying at elementary occupation, professionals technicians and associate professionals, sale and service workers, plant machine operators and assemblers, legislators senior officials and managers in comparison with clerks. The Policy measures for the current recipient old generation have need to reinforce supplemental role of Senior's pension(non-contribution pension) until maturing of public pension, because of no having chance of public pension participants for them. And the Policy measures for the future recipient working generation have need to restructure social security fundamentally corresponding with social-economic change as labour market and family structure etc. The pension system has need to change from one earner one pension to one citizen one pension with citizenship rights. At this point, public pension have need to manage with combining insurance's contribution principle and citizenship principle financing by taxes. Then public pension will become substantially universal social network for old-age income maintenance and we can find real solution for the excluded from.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.107-115
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• 2005

This paper presents the structure of a broadband coplanar waveguide(CPW) fed square slot antenna with a impedance bandwidth tuning patch. The designing method of the antenna suggests that two resonant frequencies are excited as a dual-frequency dipole antenna following the dimensions of the square slot. In other words, the lower resonant frequency mainly depends on the slot width and the higher one its length. A CPW fed square slot antenna with a impedance tuning patch was measured to $20GHz^\~33GHz$, $50\%$, VSWR=2 impedance bandwidth by adjusting the dimensions of the tuning patch when the slot length had $70\%$ of its width. This result shows that a medical CPW fed antenna is easily implemented with a simple square slot structure including a bandwidth tuning patch in the center.

• Journal of KIISE:Software and Applications
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• v.36 no.8
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• pp.653-663
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• 2009

In this paper, we propose a blind spots elimination system using three cameras. A wide-angle camera is attached on trunk for eliminating blind spots of a rear-view mirror and two cameras are attached on each side-view mirror for eliminating blind spots of vehicle's sides. In order to eliminate blind spots efficiently, we suggest a method to build a panoramic mosaic view with two side images and one wide-angle rear image. First, we obtain an undistorted image from a wide-angle camera of rear-view and calculate the focus-of-contraction (FOC) in undistorted images of rear-view while the car is moving straight forward. Second, we compute a homography among side-view images and an undistorted image of rear-view in flat road scenes. Next, we perform an image registration process after road and background region segmentation. Finally, we generate various views such as a cylinder panorama view, a top view and an information panoramic mosaic view.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.138-141
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• 2007

본 논문에서는 제작이 간편하고, 저렴하여, 설치가 용이한 Trihedral comer reflector를 연결하여 전방향(omni-directional)에서 전파를 입사방향으로 반사하도록 전파반사기를 설계한다. Scale-down된 사각(Square) 형태와 원형(circular) 형태의 Retroreflector를 제작하고 RCS(radar cross section)의 각도별 패턴 특성을 측정하여 이론적, 수치 해석적 계산과 비교한 결과를 보인다. 측정된 RCS 절대 값과 패턴을 이론식 및 시뮬레이션 수치 해석 값과 비교하여 데이터의 적정성을 분석한다.

• Korean Journal of Heritage: History & Science
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• v.43 no.4
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• pp.24-55
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• 2010

Jangmyeongdeung Lantern (貞陵長明燈) refers to the stone lantern placed in front of the royal tomb. It serves both symbolic and decorative purposes; symbolic because it is supposed to guard and illuminate the buried, and decorative because it is a work of sculpture that adorns the entire graveyard. The Jangmyeongdeung of Jeongneung was the earliest stone lantern to be produced during the Joseon period. Its square shape is unique among those from the early to mid-Joseon period. The three major parts of Jangmyeongdeung - the stand, the lantern, and the roof-shaped cover parts - are square in shape, differing from the octagonal shaped Jangmyeongdeung. The stand consists of three single stone blocks, the Hadaeseok(下臺石), Ganjuseok(竿柱石), and Sangdaeseok(上臺石). The Hwasaseok(火舍石), or the lantern part, is also a single stone block. Jangmyeongdeung of Jeongneung succeeds the style of those of Hyeon-neung and Jeongneung(玄正陵) of the Goryeo period and is of a better artistic quality. As the first Jangmyeongdeung lantern, it is a refined work of art that marks the foundation of the Joseon Kingdom. This paper tries to ascertain the stylistic origin of the square-shaped Jangmyeongdeung of Jeongneung and compare it with those of Buddhist temples. Consequently, similarities were found among the stone lanterns of Zen priests 'Jigong'(指空) and 'Nawong'(懶翁) in the Hweamsa Temple(檜巖寺) site from the late Goryeo period, those of Zen priest 'Muhak'(無學) of the Hweamsa Temple site, and those of national priest 'Bogak'(普覺) of Cheongnyongsa Temple(靑龍寺) from the early Joseon period. Primarily, this is because the three components(the stand, the lantern part, and the roof-shaped cover) are essentially square-shaped. Second, as the Ganjuseok(one of the components of the stand) became shorter, the stand took a more stable form. Third, the Hwasaseok(the lantern part) consists of two stone blocks joined together. Fourth, the roof-shaped cover is also in square in shape. Similarly, the Jangmyeongdeung of Jeongneung contains Buddhist elements as well. The three-bead pattern that decorates the Ganjuseok stand is an example. The three-bead pattern is one of the symbolic elements related to Tantric Buddhism. It is found on the diadems worn by Bodhisattvas from the Goryeo and early Joseon periods. The Jangmyeongdeung of Jeongneung in early Joseon directly influenced the production of the square-shaped stone lanterns used to decorate the tombs during the Joseon period. After the latter half of the 15th century, however, the octagonal-shaped Jangmyeongdeung style began to prevail. The Jangmyeongdeung of Jeongneung reflects the succession of the tradition of royal tombs from Goryeo to Joseon, the introduction of square-shaped stone lanterns to Buddhist temples, and the influence of the Buddhist philosophy of the time. It is a living testimony to various elements of each time and corresponding cultural trends.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2191-2201
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• 2000

End effects due to sectional deformations of thin-walled beams with closed cross section are analysed by a one-dimensional theory. In particular, end effects associated with warping (out of plane m otion) and distortion (in plane motion) are investigated. The exact solutions as a vector form are newly derived to reveal slowly-decaying nature of the end effects in a thin-walled beam loaded by a couple. Several examples of thin-walled beams under various loading conditions indicate that the local end effect zone due to warping and distortion is approximately ten times the typical beam width.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.79-84
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• 2006

The present study deals with the flow over a flat plate with repeated roughness elements of 2-dimensional rectangular shape, which can be applied into the study on the natural geographical roughness and the turbulent flow on roughened solid surface. Experiment was performed using PIV technique in the circulating water channel. Results showed that the flow over roughness elements was characterized by the high shear flow emanating from top of roughness element and the recirculating region formed at the trough of two roughness elements. In general, the ratio between the spacing and the height of roughness elements plays a crucial role in developing the flow pattern near wall surface.