• Journal of Platform Technology
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• 제9권4호
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• pp.10-31
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• 2021

최근 구글 세라고 지칭되는 디지털 세가 OECD 제31차 총회(2021. 10. 08)에서 136개국의 전폭적인 지지로 최종 합의되어 2023년부터 시행될 예정이다. 본 연구의 목적은 OECD가 글로벌 MNE를 대상으로 마련한 디지털 세에 대하여 분석하고 국내 산업에 미치는 파급효과와 우리나라의 대응 방안을 제시하는 것이다. 첫 번째 연구로 디지털 세에 대한 국제합의 내용을 분석한 결과, 글로벌 MNE가 해외 국가에 사업장을 설치하지 않더라도 매출과 이익이 발생하면 초과이익금의 25%를 세금으로 부담하고(필라1), 모든 국가에서 사업을 수행하면 최소 15%의 세금을 부담하는 것이다(필라 2). 이것은 세계 각 국가가 글로벌 MNE가 향후 자국 시장을 쉽게 잠식할 것을 예상하여 자국 기업을 보호하는 최소한의 대응책을 마련하기 위한 것으로 판단된다. 두 번째 연구는 글로벌 MNE는 왜 그렇게 강력한가? 에 대한 이유를 찾기 위해서 구글과 B2B SaaS 기업을 중심으로 동향을 분석하였다. 분석 결과, 글로벌 MNE는 디지털플랫폼 파트너십 생태계를 구축하여 해외 국가에 쉽게 진입하고 신속히 확장해 나가는 것을 발견하였다. 결론에서 우리의 대응 방안으로 산업육성정책을 창업 기업, 산업 그리고 국가 수준으로 각각 구분하여 제시하였다.

• 소성∙가공
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• 제21권3호
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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.

• International Journal of Automotive Technology
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• 제4권3호
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• pp.135-140
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• 2003

In the deterministic optimization of a structural system, objective function, design constraints and design variables, are treated in a nonstatistical fashion. However, such deterministic engineering optimization tends to promote the structural system with lest reliability redundancy than obtained with conventional design procedures using the factor of safety. Consequently, deterministic optimized structures will usually have higher failure probabilities than unoptimized structures. Therefore, a balance must be developed between the satisfactions of the design requirements and the objectives of reducing manufacturing cost. This paper proposes the reliability-based design optimization (RBDO) technique, which enables the optimum design that considers confidence level for the vibration characteristics of structural system. Response surface method (RSM) is utilized to approximate the performance functions describing the system characteristics in the RBDO procedure. The proposed optimization technique is applied to the pillar section design considering natural frequencies of a vehicle structure.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 춘계 학술대회논문집
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• pp.99-109
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• 1998

This paper describes the analysis of flow and aeroacoustic field around a car-like body. The governing equations, 3-D unsteady incompressible Navier-Stokes equations, are solved with the iterative time marching scheme. The Chimera grid technique has been applied to efficiently simulate the flow around the side-view mirror, After the flow field analysis has been converged, the aerodynamic noise analysis of the side-view mirror has been performed by solving Ffowcs Williams and Hawkings equation. From the present numerical simulation, the A- and C-pillar vortex are evidently shown and the aerodynamic noise level induced by the side-view mirror is predicted to about 100dB.

• 소성∙가공
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• 제25권5호
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• pp.295-300
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• 2016

Recently, Ultra High Strength Steel (UHSS) sheet metal has been widely used to improve lightweight structures in the automobile industry. Because UHSS sheets have high strength but low elongation, it is difficult to control winkle and thinning for complex shaped products. The draw beads on die surface were introduced in this study to reduce wrinkle and thinning. The positions and strength values of draw beads were selected as design variables and optimized using finite element analysis. The beads positions and strength of a mold for B-pillar part were designed with the proposed optimization method. The accuracy of die design from optimization was verified by comparing with the results from 3-D scanned geometry.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.156-157
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• 2007

나노임프린팅 기술을 이용하여 원기둥형 나노 패턴을 갖는 도광판을 제작하였다. 나노 임프린트 공정을 이용하기 위해서는 니켈 스탬퍼가 필요하기 때문에 이를 제작하기 위하여 실리콘 웨이퍼 상에 건식식각을 이용하여 실리콘 몰드를 제작하였다. 제작된 실리콘 몰드를 전주도금을 이용하여 니켈 스탬퍼를 제작하였다. 제작된 니켈 스탬퍼를 사용한 나노임프린트 공정을 통해 원기둥 나노패턴을 갖는 도광판을 제작하였다.

• 대한기계학회논문집B
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• 제30권2호
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• pp.136-143
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• 2006

A particle image velocimetry (PlV) technique has been applied to measure the quantitative flow field characteristics behind a road vehicle with/without an air spoiler attached on its trunk and to estimate its effect on the wake. A vehicle model scaled in the ratio of 1/43 is set up in the mid-section of a closed-loop water tunnel. The Reynolds number based on the vehicle length is $10^5$. To investigate the three-dimensional structure of the recirculation zone and vortices, measurements are carried out on the planes both parallel and perpendicular to the free stream, respectively. The results show significant differences in the recirculation region and the vorticity distributions according to the existence of the air spoiler. The focus and the saddle point, appearing just behind the air spoiler, are disposed differently along the spanwise direction. Regarding the streamwise vortices, the air spoiler produces large wing tip vortices. They have opposite rotational directions to C-pillar vortices which are commonly observed in case that the air spoiler is absent. The wing tip vortices generate the down-force and as a result, they can make the vehicle more stable in driving.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1429-1434
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• 2004

Immunoassay is one of the important analytical methods for clinical diagnoses and biochemical studies, but needs a long time, troublesome procedures and expensive reagents. In this study, therefore, we propose the micro filter chip with microbeads for immunoassay, which has pillar structures. The advantage of the proposed micro filter chip is to use simple fabrication process and cheap materials. The mold was made by the photolithography technique with Si wafer and negative photoresist SU-8. The replica was made of PDMS, bonded on the pyrex glass. The micro filter chip consists of inlet channel, filter chamber and outlet channel. HBV (Hepatitius B virus) monoclonal antibody (Ag1) labeled with biotin were immobilized onto streptavidin coated beads of 30∼50 $\mu$m size. Fluorescein isothiocyanate (FITC)-labeled HBV monoclonal antibody (Ag8) was used to detect HBsAg (Hebatitis B virus surface Antigen), and fluorescence intensity was monitored by epi-fluorescence microscope. In this study, the immune response of less than 30 min was obtained with with the use of 100 $m\ell$ of sample.

• 대한기계학회논문집B
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• 제29권1호
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• pp.151-158
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• 2005

A characteristic of discharge for a foam spray nozzle with various parameters was investigated. The discharge patterns from a fire foam spray nozzle are important to evenly spray over a maximum possible floor area. Two parameters of a foam spray nozzle were chosen, and compared with those from the standard one. Also, in order to evaluate the performance of discharged foam agents used to protect structures from heat and fire damages, the thermal characteristics of fire-protection foams were experimentally investigated. A simple repeatable test for fire-protection foams subjected to fire radiation was developed. This test involves foam generation equipment, a fire source for heat generation, and data acquisition techniques. Results show that the bubble size of foam is increased by large inside diameter of orifice or closed air hole, but phenomenon of discharge angle and expansion ratio is opposite. For the case of the open air hole, liquid film of a circular cone discharges with formation, growth, split and fine grain. In case of the closed air hole, a pillar of foam solution discharges with that. Though the temperature gradient in the foam increases with increased foam expansion ratio. it is not change with increased intensity of heat flux.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.119-123
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• 2013

We conduct the research for reducing aeroacoustic noise occurred when a vehicle operates in high speed situation without modifying the structural configuration such as deforming A-pillar's side curvature. We introduce PAU (Pneumatic Auxiliary Unit) which is a sort of air duct using intake air through radiator grill. According to our research, we can reduce overall noise levels around the surface of HSM (Hyundai Simplified Model). When a vehicleruns 100km/s, area-weighted acoustic power level (AWAPL) indicates 33dB without PAU. However with PAU, coverall AWAPL is decreased to 29dB which means we can improvesilentness approximately 12% compared to ordinary case. Moreover we conduct similar implementation to steering situation especially about yawing. In varioussituations, -10, 0, 10 degree of yawing, we observe 10% reduction in the upstream region of HSM but little increase in downstream region. It seems that inlet air overlap turbulent kinetic energy to surrounding flow. Even though downstream region's noise is louder than upstream region, overall AWAPL is still lower than conventional condition. We also apply this scheme to the real vehicle situation, then we get reasonable output which can support our research outputs.