• 한국자동차공학회논문집
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• 제5권5호
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• pp.197-212
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• 1997

The performance of a torque converter can be expressed by the performance parameters such as flow radius and flow angle, on the mean flow path. The geometric analysis of the torque converter is required to determine these parameters for the modeling of the torque converter. In general, the blade shape is depicted by three dimensional data at the mid-surface of blade or those of the pressure and suction side. To generate three dimensional model of the blade using the data mentioned above, a consistent data format and a shape generation algorithm are required. This paper presents a useful consistent data format of the blades and an algorithm for the geometrical shape generation. By the geometric analysis program to which the shape generation algorithm is embedded, the variation of blade angles in rotating element analyzed. Then finally, the analyzed results of geometric profile of a blade are compared with those of the blade design principle, so called forced vortex theorem.

• 대한기계학회논문집A
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• 제20권1호
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• pp.180-188
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• 1996

The stress singularity of a sharp wedge contacting a half plane can be avoided by changing the wedge shape. Shape optimization is accomplished with the geometric strain method (GSM), an optimality criterion method. Several numerical examples are provided for different materials in the wedge and half plane to avoid stress singularity neal the sharp corner of the wedge. Optimum wedge shapes are obtained and critical corner angles are compared with the angles from analytical contact mechanics. Numerical results are well matched to analytical and experimental results. It is shown that shape optimization by the geometric strain method is a useful tool to reshape the wedge and to avoid a stress singulatiry. The method applies to more general geometries where the singular behavior would be difficult to avoid by classical means.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.683-688
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• 1994

Recently, the Z-Map model has been used widely to represent the three dimensional geometric shape and to achieve the cross-section and point evaluation of the shape. In this paper, the CNC cutting planning and simulation modules for product with three dimensional geometric shape are realized based on the Z-Map model. The realized system has the various capabilities related to the automatic generation of tool path for the rough and finish cutting processes, the automatic elimination of overcut, the automatic generation of CNC program for a machining center and the cutting simulation. Especially, the overcut-free tool path is obtained by using the CL Z-Map models which are composed of the offset surfaces of the geometric shape of product.

• 한국정밀공학회지
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• 제13권5호
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• pp.115-121
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• 1996

Recently, the Z-Map model has been used widely to represent the three dimensional geometric shape and to achieve the cross-section and point evaluation of the shape. In this paper, the CNC cutting planning and simulation modules for product with three dimensional geometric shape are realized based on the Z-Map model. The realized system has the various capabilities related to the automatic generation of tool path for the rough and finish cutting processes, the automatic elimination of overcut, the automatic generation of CNC program for a machining center and the cutting simulation. Especially, the overcut-free tool path is obtained by using the CL Z-Map models which are composed of the offset surfaces of the geometric shape of product.

• 복식
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• 제39권
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• pp.99-111
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• 1998

Cubism has played a great role to change traditional concept of art and visual of people as developed into one of new art stlyes. It has avoided three dimensional perspectives and reformed the concept of time and space. It expresses objects with geometric shape by simplifying and reconstructing the objects after taking them apart. This has the effect of simultaneous vision and transparency and brings in collage by combining geometric image and visual elements. The results of the study as follows: First, the geometric shape expresses straight lines, curves, faces, and cubics by simplifying the objects. In fashion, it expresses circles, triangles, squares with a cloth. This shows visual changes as three dimensional space moves. Second, simultaneity disassembles and recontructs the objects. It tries to understand the internal shape with method of disassembling and makes visions coexist. In so doing, cubists adopt simultaneity for expressing shapes. In fashion, it expresses new items through disassembling or combining with other items. Third, transparency simplifies cubics by duplicating with transparent flats and crosses contour lines for reconstructing the simplified objects. This implies broader spatial order. It allows people to perceive penetration of layed clothes. Fourth, collage expresses geometric shape by adding visual elements(concrete image and color). It uses concrete image with paper, letters, cloth, etcs, which is not related to painting, and introduces various colors. In fashion, it uses dolls, postcards, feathers, metals, plastics, for patchwork.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권3호
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• pp.313-321
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• 2012

Vibration analysis of a thin-walled structure can be performed with a consistent mass matrix determined by the shape functions of all degrees of freedom (d.o.f.) used for construction of conventional stiffness matrix, or with a lumped mass matrix. In similar way stability of a structure can be analysed with consistent geometric stiffness matrix or geometric stiffness matrix with lumped buckling load, related only to the rotational d.o.f. Recently, the simplified mass matrix is constructed employing shape functions of in-plane displacements for plate deflection. In this paper the same approach is used for construction of simplified geometric stiffness matrix. Beam element, and triangular and rectangular plate element are considered. Application of the new geometric stiffness is illustrated in the case of simply supported beam and square plate. The same problems are solved with consistent and lumped geometric stiffness matrix, and the obtained results are compared with the analytical solution. Also, a combination of simplified and lumped geometric stiffness matrix is analysed in order to increase accuracy of stability analysis.

• 한국CDE학회논문집
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• 제1권3호
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• pp.215-223
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• 1996

Every mechanical part is fabricated with the variations in its size and shape, and the allowable range of the variation is specified by the tolerance in the design stage. Geometric tolerances specify the size or the thickness of each shape entity itself or its relative position and orientation with respect to datums while considering their order of precedence. It would be desirable if the assemblability of parts could be verified in the computer when the tolerances on the parts are store together with the geometric model of the parts of an assembly and their assembled state. Therefore, a new method is proposed to represent geometric tolerances and to determine the assemblability. This method determines the assemblability by subdividing the ranges of relative motion between parts until there exists the subdivided regions that do not cause the interference.

• 한국CDE학회논문집
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• 제8권4호
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• pp.243-253
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• 2003

This paper presents a new geometric morphing algorithm for polygons based on a simple geometric structure called direction map, which is mainly composed of a circular list of direction vectors defined by two neighboring vertices of a polygon. To generate a sequence of intermediate morphing shapes, first we merge direction maps of given control shapes based on a certain ordering rule of direction vectors, and scale the length of each direction vectors using Bezier or blossom controls. We show that the proposed algorithm is an improvement of the previous methods based on Minkowski sum (or convolution) in th aspects of computational efficiency and geometric properties.

• 디자인학연구
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• 제18권2호
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• pp.325-334
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• 2005

본 연구는 20세기 디자인교육에 있어서 기하학적인 형태에 나타난 조형원리의 근원을 탐색하는 것이다. 디자인 교육에 등장한 기하학적인 형태는 19세기 독일을 중심으로 일어난 유치원 운동에서 도입된 교육사상에서부터 출발한다. 19세기 독일의 유아교육자 프뢰벨(Friedrich $Fr{\ddot{o}}bel$)에 의하여 탄생된 프뢰벨교구(Spielgaben)의 인기는 학교에서의 미술교과목에서 도구를 사용하게 되는 계기를 마련하게 된다. 과학적이고 수학적인 원리에 의하여 만들어진 프뢰벨교구는 최소한의 색채와 형태를 채택한 어린이를 위한 교육프로그램이었다. 19세기 기하형태의 블록놀이를 중심으로 개발된 '슈필가벤(Spielgaben)'과 '작업($Bech{\ddot{a}}ftigungsmaterial$)'이란 이름으로 진행된 놀이프로그램은 초기모더니스트들에 의해 기하형태에 대한 선택으로 이어지게 된다. 또한 20세기 현대디자인교육의 시작이 되었던 바우하우스의 기초교육프로그램에서도 적용된다. 이러한 사실에서 20세기 디자인교육에서 나타난 점선면의 원리와 기하학적 형태의 선택에 대한 근원적 배경을 찾을 수 있다. 따라서 본 연구는 유치원운동과 근대디자인교육과의 기하학적인 형태라는 동일한 범주 속에서의 연관성에 대한 논의이다. 즉, 이러한 연관성에 대하여 문헌조사를 통하여 탐색하고 서로의 관계에 대하여 분석하고 비교하여 연구하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.32.6-32
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• 2002

The damage localization of the structural system using the natural frequency measurement only is proposed. The existing methods use the changes of mode shape, strain mode shape or curvature mode shape before and after the damage occurrence as these shapes carry the geometric information of the structure. Basically, the change of natural frequencies of the structure can be used as the indicator of the damage occurrence but not as the indicator of the damage location as the natural frequency changes does not carry the geometric information of the structure. In this research, the feedback scope method that measures the natural frequency changes of the structure with and without the feedback Ioo...