• Proceedings of the KSME Conference
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• 2008.11a
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• pp.844-849
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• 2008

A nano-imprinting stage has been widely used in various fields of nano-technology. In this study, A 4-axis nano-imprinting stage is modeled with using the 3D-CAD Tool. Structural components such as an upper-plate, bearings and cross-roller-guides are modeled with finite elements to analyze flexibility effect during the precision stage motion. In addition, Dynamic analysis is executed to reproduce actual motion of 4-axis nano imprinting stage.

• 연구논문집
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• s.25
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• pp.67-76
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• 1995

A grid generation algorithm associated with turbomachinery cascade flow fields has been developed. The present grid generation system consists of four separate modules. The system input is made of the results of the preliminary design, i.e., flow-path, aerodynamic conditions along the spanwise direction, and the blade profile data. The grid generation method generates a series of two-dimensional grids in the blade-to-blade passage to build up the three-¬dimensional grid, The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The resultant grids generated from each module of the system are used as the preprocessor for the performance prediction of the turbomachinery blade using Naveir-Stokes method in addition to the blade surface modelling for CAD data. For purposes of illustration, the grid generation system is applied to several complex geometries inculding a turbine rotor with and without a tip flow grid. Application to the blade design of the LP compressor was demonstrated to be very reliable and practical in support of design activities. This customized system are coupled strongly with the design procedure and reduces the man-hours required to predict the aerodynamic performance of the turbomachinery cascades using the CFD technique.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.635-636
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• 2006

A knowledge-based system with CAD is widely used to implement a designer's know-how and a routine calculation within a system. An engineer needs to change several design parameters in an early design stage. However it is not easy to change the design parameters when it needs to update an existing model and data. In this paper, a module has been proposed to make it easy to change the design parameter so that the engineer can easily update and change the design model. Also a flexible interface of the module can easily add or extract the design knowledge.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.581-582
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• 2006

This paper presents an integrated machining error compensation method based on PNN(Polynomial Neural Network) approach and inspection database of OMM(On-Machine-Measurement) system. To efficiently analyze the machining errors, two machining error parameters are defined and modeled using the PNN approach, which is used to determine machining errors for the considered cutting conditions. Experiments are carried out to validate the approaches proposed in this paper. In result, the proposed methods can be effectively implemented in a real machining situation, producing much fewer errors.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.305-311
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• 2005

The die development of the high-strength steel sheet has big difference on the formability compared with the general panels. Especially, the springback after stamping of the high-strength steel sheets shows big problem. In this study, for the die development of the high-strength steel sheets, write about examples reducing the lead time and the expense of the die development after CAD modification with the result of the springback analysis after finding the best design planning as several times stamping analysis.

• International Journal of CAD/CAM
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• v.9 no.1
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• pp.55-60
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• 2010

Quadratic B$\acute{e}$zier curves are important geometric entities in many applications. However, it was often ignored by the literature the fact that a single segment of a quadratic B$\acute{e}$zier curve may fail to fit arbitrary endpoint unit tangent vectors. The purpose of this paper is to provide a solution to this problem, i.e., constructing $G^1$ quadratic B$\acute{e}$zier curves satisfying given endpoint (positions and arbitrary unit tangent vectors) conditions. Examples are given to illustrate the new solution and to perform comparison between the $G^1$ quadratic B$\acute{e}$zier cures and other curve schemes such as the composite geometric Hermite curves and the biarcs.

• 연구논문집
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• s.33
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• pp.89-97
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• 2003

A barrel cam is used as a very important part of an index drive unit. The index drive unit must have an intermittent-rotational motion. The barrel typed cam and roller gear mechanism has the advantages of high reliability to perform a prescribed motion of a follower. This paper proposes a new method for the shape design of the barrel cam and also a CAD program is developed by using the proposed method. As defined in this paper, the relative velocity method for the shape design calculates the relative velocity of the follower versus cam at a center of roller, and then detemines a contact point by using the geometric relationships and the kinematic constraints, where the direction of the relative velocity must be parallel to a common tangential line at the contact point of two independent bodies, i.e. the cam and the follower. Then, the shape of the cam is defined by the coordinate transformation of the trace of the contact points. This paper presents shape design of the barrel cam in order to prove the accuracy of the proposed methods

• Electronics and Telecommunications Trends
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• v.21 no.4 s.100
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• pp.12-21
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• 2006

3차원 메시 모델은 컴퓨터 그래픽스, 애니메이션, 3D 모델링, CAD, 3D 게임 등의 다양한 응용 분야에서 광범위하게 사용되고 있다. 그러나, 현실감을 줄 수 있는 고해상도의3차원 모델은 그 정보량의 방대함으로 인해 처리, 저장, 전송 등에 있어 여러 가지 어려움이 따른다. 따라서, 이를 효율적으로 압축하여 저장 및 전송하기 위한 3차원 메시 모델 부호화 기술이 연구되어 왔다. 본 고에서는 3차원 메시 부호화 기술에 대한 연구 개발 동향과 이에 대한 표준화 동향을 소개한다. 또한, 3차원 메시 부호화 기술과 관련하여 ETRI에서 연구중인 정점 및 면 순서 정보 부호화 기술과 텍스처 좌표 부호화 기술의 내용과 이에 대한 연구 활동 현황을 요약하고, 주요 이슈 논의 및 향후 전망에 대해 간략히 살펴보고자 한다.

• Proceedings of the IEEK Conference
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• summer
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• pp.339-342
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• 2004

In this paper, we investigated methods to reduce SAR(Specific Absorption Rate) value with EMI(Electromagnetic Interference) paint distribution on front case of mobile handset. Simulations for several different EMI patterns were carried out. For the purpose of modeling, we used 3 dimensional CAD(Computer Aided Design) program, `Pro-engineering'. SAR simulation was done with SEMCAD, simulation platform for electromagnetic compatibility antenna design and dosimetry. In order to distinguish the individual pieces and to enable an assignment of the different material properties, each subfile was imported separately. In simulation, folding angle was set to $142^{\circ}.$ If we vary folding angle, different SAR value will be obtained. Among the tested EMI paint patterns, the hairpin pattern showed the best performance, i.e. the decrease efficiency of $16.5\%$ and horizontal-direction zigzag pattern showed the decrease efficiency of $12.2\%$ when we set the completely removed pattern as reference.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.4
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• pp.13-24
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• 1994

The demand of clean energy, like liquefied gas(LNG), increase suddenly because it generates few polluting substances when burned and from the point of view with caloric value it generates ralatively less $CO_2$ gas than the other energy sources. LNG transpotion method of our country is marine transportion by ships because the LNG producing district is far away from Korea. Main engines for most LNG ships are steam turbines, and the efficiency of steam turbine is influenced by the degree of vacuum of main steam condenser. This paper introduce the design method of the vacuum system for high efficiency marine steam turbine. Especially, it is developed the CAD program for the large steam condenser and steam ejector. Also, it is designed the pilot plant including high pressure boiler for the performance test and maked a part of this plant.