• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.62-68
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• 2012

Geometry of a screw fabricated by a turning process determined by the shape of the tool, feed rate of the tool and rotation speed of the spindle. Therefore, computing the exact geometry of the screw is very important to perform a simulation on machining or an evaluation of the workpice quality. In this paper, a new mathematical geometry model of the 3 dimensional screw is fabricated by turning process introduced for the exact geometry computation. Becasue model has a parametric formulation, it is easy to process for a CAD geometry or apply for a machining simulation. Also, it can be applied to process planning because it gives precise machined geometry on whole the 3 dimensional surface of the screw. This paper introduces a new parametric model of a geometry for screw fabricated by turning process. As an application, a simulation software for the 3 dimensional screw surface is developed and evaluated for several manufacturing parameters.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.126-134
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• 2003

In this study we do for the thing to develop automatic geometry design program of a mechanical element that we have used in CAD/CAM system. The program, which produces automatically three-dimensional surface and a solid model that have been used in CAD/CAM system, widely create automated two and three-dimensional model to by inputting several necessaries for a design, fur the design element. It is emphasized if you are just a beginner having only basic knowledge of the mechanical engineering, you might be able to design easily a three-dimensional model. The software to be used to develop automatic geometry design program is visualLISP to be a developer program of AutoCAD.

• Bulletin of the Korean Mathematical Society
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• v.49 no.5
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• pp.1101-1129
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• 2012

We study the geometry of the images of 1-dimensional homogeneous submersions for each of the model spaces X of the eight 3-dimensional geometries. In particular, We shall calculate the group of isometries and the curvatures of the base surfaces for each of the model spaces of 3-dimensional geometries, with respect to every closed subgroup of the isometries of X acting freely.

• Journal of the Korea Society for Simulation
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• v.11 no.3
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• pp.13-22
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• 2002

This paper describes an automated evaluation of electrostatic field for micro motors whose sizes range 10 to 103um. Electric field modeling in micro motors has been generally restricted to in-plane two-dimensional finite element analysis (FEA). In this paper, the actual three-dimensional geometry of the micro motor is considered. An automatic FE mesh generation technique, which is based on the fuzzy knowledge processing and computational geometry techniques, is incorporated in the system, together with one of commercial FE analysis codes and one of commercial solid modelers. The system allows a geometry model of concern to be automatically converted to different FE models, depending on physical phenomena to be analyzed, electrostatic analysis and stress analysis and so on. The FE models are then exported to the FE analysis code, and then analyses are peformed. Then, analytical analysis and FE analysis about the torque generated by electrostatic micro motor are performed. The starting torque is proportional to $V^2$, the calculated starting torque from the two-dimensional analytical solutions are three times larger than those from the three-dimensional FE solutions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.954-957
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• 2004

Based on the authors' previous work, where a geometric constraint handling technique for stiffener layout optimization problem using geometry algorithms was proposed, stiffener layout optimization to maximize natural frequencies of a curved three-dimensional shell structure was performed with a projection method. The original geometry of the shell structure was first projected on a two-dimensional plane, and then the whole optimization process was performed with the projected geometry of the shell except that the original shell structure was used for the eigenproblem solving. The projection method can be applied to baseline structures with a one-to-one correspondence between original and projected geometries such as automobile hoods and roofs.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.3
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• pp.14-21
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• 1994

In this paper, a numerical method to be obtain the radar cross section(RCS) of three- dimensional bodies with arbitrary geometry and material compositions on the electromagnetic field with arbitrary incident angle is described. The RCS is obtained by solving the individual surface integral equation about multilayers scatterer using the three-dimensional bonudary element method(BEM). To show propriety and usefulness as to the three-dimensional BEM in this paper, the choice of a geometry is a multi-regular hexahedron and multi-right-angled hexahedron out of oblique incident electric field, and is considered to apply to every condition with loss sufficiently.

• Journal of applied mathematics & informatics
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• v.5 no.2
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• pp.349-356
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• 1998

We give the new formulas counting the total number of all lines planes and tetrahedrons in the n-dimensional Boolean space.

• Proceedings of the IEEK Conference
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• summer
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• pp.137-142
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• 2004

In this paper, we propose a new scheme for geometry coding of three-dimensional (3-D) mesh models using a fixed spectral basis. In order to code the mesh geometry information, we generate a fixed spectral basis using the dual graph derived from the 3-D mesh topology. After we partition a 3-D mesh model into several independent sub-meshes to reduce coding complexity, the mesh geometry information is projected onto the generated orthonormal bases which are the eigenvectors of the Laplacian matrix of the 3-D mesh. Finally, spectral coefficients are coded by a quantizer and a variable length coder. The proposed scheme can not only overcome difficulty of generating a fixed spectral basis, but also reduce coding complexity. Moreover, we can provide an efficient multi-resolution representation of 3-D meshes.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.514-519
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• 1996

In this study, an investigation on the geometry control of the precast segmental method(PSM) was performed and GEOCON was developed. It is an interactive software to control the 3-dimensional geometry of precast segmental bridges during the construction progress. Specially, this paper emphasized that the fabrication stage of the precast segment is the most important for the geometry control in the PSM and also descussed about some problems which can be overlooked in developing and using the geometry control softwares by explaining the GEOCON's characteristics. GEOCON was successfully applied to the surrounding road of Pusan harbor.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.3
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• pp.43-49
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• 2001

When designing a gerotor, designers determine basic dimensions of a gerotor with transmitted power considering strength, interference and so. on. But, designers can not easily obtain the tooth profile generated by dimensions as well as the geometry bob for cutting the tooth profile. In order to resolve these problems, an automatic design sys-tem creating not only the solid model of a gerotor but also that of the generating hob using the design parameters of dimen-sions is developed. Through the developed system, designers can improve the efficiency of design and satisfy the variable requirements of design as well. In this research, the three-dimensional solid models for gerotors are generated considering the design parameters. Besides, those for generating hob regarding the design parameters of hob is created automatically.