• 한국전자통신학회논문지
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• 제2권4호
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• pp.222-227
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• 2007

ISO15754 표준의 개방형 객체 모델링 및 프로파일링 기술을 적용하여 개발할 휴머노이드 로봇의 설계 및 구현에 대한 개방화된 개발 방법론을 제안한다.

• 한국정밀공학회지
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• 제10권2호
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• pp.40-47
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• 1993

To diversify the area of application of UBET to the analysis of ring rolling which produces rings having more complex cross-sectional configuration, an element of triangular cross-section has been introduced and the corresponding kinematically admissible velocity field has been derived while considering the material flow between neighboring elements. The theoretical perdictions in roll torque and profile formation show good agreement with the experiments. The effect of process parameters such as feed rate and taper angle of the roll groove has been discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.1043-1046
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• 2002

A 50% reduction of convergence errors of CRT's is achieved by a technique referred to as 'Magnetically Improved Color Alignment' or MICA for short. The MICA technology comprises a ring of synthetic material (polymer) filled with ferrite particles. MICA is meant for repairing CRT's, which are out of convergence specification. The repairing occurs by writing a magnetic correction profile in the ring.

• 한국안전학회지
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• 제22권5호
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• pp.13-20
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• 2007

Elastomeric O-ring seals are widely used in static and dynamic applications. A compressed and highly pressurized O-ring seal inserted under laterally one-sided constrained condition has been analyzed experimentally and numerically. The deformed shape and extrusion length of the O-ring under high pressure has been measured by the computed tomography. Through the comparison of experimental and FE results, the numerical analysis technique has been verified. Using verified FE method, the contact stress profiles at sealing surfaces have been investigated and their relevance to the 0-ring performance evaluated based on stress-related and displacement-related parameters. It has been found that the contact stress profiles and deformation behaviors of the seal are affected by friction coefficient, gap clearance, and pressure considerably.

• 한국정밀공학회지
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• 제14권8호
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• pp.92-100
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• 1997

An upper-bound elemental technique (UBET) analysis is carried out to improve the material flow and to reduce the load of bearing-race forming process. The UBET analysis, which adapts the advantages of stream function and finite element method, is useful for predicting the profile of complex geometric bound- ary. From the UBET analysis, the forming load, the velocity distribution and the stream line of the deformed billet are determined by minimizing the total power consumption with respect to chosen parameters. The results of present UBET analysis are better than those of previous UBET analysis. Experiments have been carried out with model material plasticine billets at room temperature. The theoretical predictions for forming load and flow pattern(stream line) are in good agreement with the experimental results.

• 대한의용생체공학회:의공학회지
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• 제25권5호
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• pp.351-359
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• 2004

속도계측형 호흡기류센서는 베르누이 원리에 의해 기류속도를 동압력으로 변환하여 호흡기류를 측정하는 센서로써 다수의 샘플링 구멍을 기류통과면 상에 설치해야 한다. 본 연구에서는 속도 샘플 구명들을 비균등하게 배치시킴으로써 단순하게 균등 배치하는 것보다 훨씬 정확한 기류 계측이 가능함을 이론적으로 입증하였다 컴퓨터 시뮬레이션 결과 기류통과면을 다수의 등면적 링으로 분한하고 각각의 링의 면적을 다시 2등분하는 위치에서 속도를 샘플링함으로써 균등 배치할 경우에 비해 계측오차가 약 1/5로 감소하였다. 또한 충 샘플개수가 4개 이상이면 상대오차 1％ 이내의 매우 정확한 기류계측이 가능하였다. 기류 속도분포의 변화에 따른 영향을 비교한 결과 균등 샘플링에 비해 1/2 이하로 둔감하였다. 따라서 본 인구에서 제안하는 비균등 속도샘플링 기법은 속도 계측형 호흡기류센서의 설계시 매우 유용하게 적용될 것으로 판단된다.

• Korea-Australia Rheology Journal
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• 제21권3호
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• pp.193-200
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• 2009

We present a direct simulation technique for two-dimensional mold-filling simulations of fluids filled with a large number of circular disk-like rigid particles. It is a direct simulation in that the hydrodynamic interaction between particles and fluid is fully considered. We employ a pseudo-concentration method for the evolution of the flow front and the DLM (distributed Lagrangian multipliers)-like fictitious domain method for the implicit treatment of the hydrodynamic interaction. Both methods allow the use of a fixed regular discretization during the entire computation. The discontinuous Galerkin method has been used to solve the concentration evolution equation and the rigid-ring description has been introduced for freely suspended particles. A buffer zone, the gate region of a finite area subject to the uniform velocity profile, has been introduced to put discrete particles into the computational domain avoiding any artificial discontinuity. From example problems of 450 particles, we investigated the particle motion and effects of particles on the flow for both Newtonian and shear-thinning fluid media. We report the prolonged particle movement toward the wall in case of a shear-thinning fluid, which has been interpreted with the shear rate distribution.

• Progress in Superconductivity
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• 제8권1호
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• pp.8-15
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• 2006

The size of the superconducting domains and the critical current density inside these domains have to be enhanced for most of cryomagnetic applications of melt-textured YBCO bulks. To enlarge the size of the domains we studied the multi-seeding technique based on a well-established procedure for preparing high quality YBCO monoliths using self-made SmBCO seeds. The distance between the seeds was optimised as a result of the investigation of the effects of various seed distances on the characteristics of the grain boundary Junctions. The influences of a-b plane intersections and c-axis misalignments were researched. Thereby, a small range of tolerance of the misorientations between the seed crystals was found. Field mapping was applied to control the materials quality and the superconductor's grain structure was investigated using polarisation microscopy. YBCO function elements with iou. seeds in a line and an arrangement of making type (100)/(100) and (110)/(110) boundary junctions, respectively, were processed. The trapped field profile in both sample types shows single domain behaviour. To demonstrate the potential of the multi-seeding method a ring-shaped sample was processed by placing sixteen seeds in a way to make both (100)/(100) and (110)/(110) grain junctions at the same time. The results up to now are very promising to prepare large single domain melt-textured YBCO semi-finished products in complex shapes.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 추계학술발표회 논문집
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• pp.99-104
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• 2004

Recently, the old surveying method for acquiring surveying-geo information results had a low economic efficiency and a low dependence of precision because it took much times and high costs. So, we acquired law data by execution of control surveying through Static positioning of DGPS(Ashtech). It is computed plainmetric(X, Y) positioning through postprocessing by Prism S/W. And we computed height(Z) through control surveying by ring-closed leveling surveying. After control surveying execution, we built DEM(Digital Elevation Model) using LDT S/W and accuracy 3D detail surveying by EDM(Electronic Distance Measurement) surveying. The purpose of this study was to yield automated digital mapping and the automated amount of materials using ahead data. The conclusions were as follows; First, we built the automated amount of materials system and got high efficiency about personnel, times and precision. Second, when, people precisely positioned on railroads of a high-speed railroad and used GPS surveying, the result was permitted. Finally, it was possible to draw automated profile and cross-section using the 3D terrain model build with the DEM technique.

• 한국전산구조공학회논문집
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• 제25권6호
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• pp.477-485
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• 2012

내압구조물의 구조적 성능에 영향을 주는 주요 요소로 형상, 쉘 두께, 보강재 배치 안 그리고 제작 재료 등을 나열할 수 있다. 전통적인 이론적 방법론에 근거한 내압구조물의 설계는 신속하며 만족할 만한 결과를 제공하지만 이는 일부 특정한 형상, 쉘 두께 및 제작 재료 등에 제한되어 있다. 본 논문에서는 최적화된 형상, 쉘 두께, 보강재 배치 안 그리고 복합재료 적층 정보 등을 얻을 수 있는 최적설계 기법에 근거한 진보된 대체 방법론을 다루고 있다. CAE 기반의 최적설계 기법을 활용하여 내압구조물 설계에 요구되는 구조적 성능과 최적화된 설계 인자들을 얻었다. 상용화된 유한요소 프로그램임 ANSYS의 CAE 플랫폼으로부터 메타모델 기반 최적화 기법을 수행하여 원통형 내압구조물의 설계를 위한 최적의 타원형 형상을 결정하였다. 또한 최적설계 프로그램인 OptiStruct의 기울기 기반 최적설계 방법을 이용하여 복합재료 기반 내압구조물의 설계시 최적의 적층순서와 쉘 두께가 얇은 내압구조물에 대한 최적의 보강재 배치 안을 각각 도출하였다. 최적설계 예제를 통해 본 논문에서 제시하고 있는 최적설계 기법에 근거한 방법론이 내압구조물의 설계에 효과적임을 확인할 수 있었다.