• 한국CDE학회논문집
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• 제5권4호
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• pp.336-346
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• 2000

This paper presents a geometric method that can detect and compute all conic sections in the intersection of two tori. Conic sections contained in a torus must be circles. Thus, when two tori intersect in a conic section, the intersection curve must be a circle as well. Circles in a torus are classified into profile circles, cross-sectional circlet, and Yvone-Villarceau circles. Based on a geometric classification of these circles, we present a procedural method that can detect and construct all intersection circles between two tori. All computations can be carried out using simple geometric operations only: e.g., circle-circle intersections, circle-line intersections, vector additions, and inner products. Consequently, this simple structure makes our algorithm robust and efficient, which is an important advantage of our geometric approach over other conventional methods of surface intersection.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권4호
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• pp.177-184
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• 2010

In this study, geometric modeling techniques and their application to ship modeling and design are presented. Traditionally the hull shape is defined by using curves called the lines and various necessary computations are performed based on the discrete points obtained from the lines. However, some applications find difficulty in using the lines such as seakeeping analysis, which requires the computation of wetted part that is changing dynamically over time. To overcome such a problem and increase accuracy and efficiency in computation, two essential geometric modeling techniques, surface modeling and surface-to-surface intersection, are introduced and their application to ship modeling and analysis including hydrostatic computation, slamming and seakeeping analyses is presented.

• 한국생산제조학회지
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• 제19권2호
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• pp.178-183
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• 2010

Base-mounted type(BMT) driving assembly in CNC machine tools is an indispensable part to improve productivity by reducing tool changeover time and to meet the ever-increasing demand of precision machine tools. This study aimed to perform finite element analysis and geometric parameter optimization to improve the efficiency of BMT driving assembly. First, simulations for three-dimensional structural and vibration analysis were performed using ANSYS/Workbench on the initial geometric models of BMT driving assembly. After analyzing stress and deformation concentration zones, several new geometrical models were designed and evaluated by design of experiments and ANSYS/DesignXplorer. Through a series of analysis-evaluation-modification cycles, it was seen that designed models were effective in determining optimal geometry of BMT driving assembly.

• Journal of Communications and Networks
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• 제17권3호
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• pp.241-246
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• 2015

In this paper, we consider a relaying system which employs a single relay in a wireless network with distributed sources and destinations. Here, all source, destination, and relay nodes are equipped with multiple antennas. For amplify-and-forward relay systems, we confirm the achievable sum rate through a joint multiple source precoders and a single relay filter design. To this end, we propose a new linear processing scheme in terms of maximizing the sum rate performance by applying a blockwise relaying method combined with geometric programming techniques. By allowing the global channel knowledge at the source nodes, we show that this joint design problem is formulated as a standard geometric program, which can guarantees a global optimal value under the modified sum rate criterion. Simulation results show that the proposed blockwise relaying scheme with the joint power allocation method provides substantial sum rate gain compared to the conventional schemes.

• 한국CDE학회논문집
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• 제12권5호
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• pp.344-353
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• 2007

In this paper, we address the problem of robust geometric modeling with emphasis on surface to surface intersections. We consider the topology and the numerical accuracy of an intersection curve to find the best approximation to the exact one. First, we perform the topological configuration of intersection curves, from which we determine the starting and ending points of each monotonic intersection curve segment along with its topological structure. Next, we trace each monotonic intersection curve segment using a validated ODE solver, which provides the error bounds containing the topological structure of the intersection curve and enclosing the exact root without a numerical instance. Then, we choose one approximation curve and adjust it within the bounds by minimizing an objective function measuring the errors from the exact one. Using this process, we can obtain an approximate intersection curve which considers the topology and the numerical accuracy for robust geometric modeling.

• 한국CDE학회논문집
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• 제3권4호
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• pp.293-303
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• 1998

The objective of this study is to develop a PC level freeform surface modeling system which explicitly represents information of part geometry. Surface modeler uses nonuniform rational B-spline (NURBS) function with nonuniform knot vector for the flexible modeling work. The results of this study are as follows. 1) By implementation surface modeler through applying representation scheme proposed to represent free-form surface explicity, the technical foundation to develop free-from surface modeling system using parametric method. 2) Besides the role to model geometric shape of a surface, geometric modeler is developed to model arbitrary geometric shape. By doing this, the availability of the modeling system is improved. Geometric modeler can be utilized application fields such as collision test of tool and fixture, and tool path generation for NC machine tool.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2004년도 추계학술발표대회 논문집
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• pp.92-97
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• 2004

This purpose of this study was about the analysis on the dynamic expression of geometric manipulation in interior composition elements. The paradigm of contemporary times became different from paradigm of modern times. The change of paradigm is caused by the side effect of paradigm of pre-times. In the contemporary architectural condition, architecture have a tendency to plural characteristics. This study investigates systemically ‘the DYNAMISM’ as a part of contemporary interior space's feature, based on geometric manipulation in interior composition elements. First of all, the dynamic characteristics of architectural space. The second, relationship between the architecture and geometric manipulation.

• 한국가구학회지
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• 제26권4호
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• pp.314-327
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• 2015

20th century, beginning of modern, the style of art and design, separated reasonable and sensitive code. Art form including cubism, constructivism, futurism and different form including fauvism, expressionism, surrealism and abstract expressionism coexist two code in early modern. But the style of design was separated each period with geometric and organic form, reasonable and sensitive code. Replacement timing on two design style was the transition period of the production-oriented step to the sale-oriented step in marketing. In early stage modern it was stable production-oriented step. Geometric style include G. Rietvevld (Red and Blue chair), M. Breuer (Wassily chair), Fanizon and Martinelli (I-Ching) was simple and functional, received the absolute support. An aggressive demand generation and sales promotion for the design change was needed so that excess supply in the market with a stable production. In sale-oriented step for sales promotion in mid modernism, it was accepted transitions to the sensual organic volume with elegant and sleek style include C. Eames (LCW chair), V. Panton (Panton chair) and C. Mollino (Arabesco Tea table).

• Architectural research
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• 제15권4호
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• pp.207-214
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• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.561-567
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• 2008

The objectives of this study is to: (1) develop how applications for driving simulator of national highway safety designs when those are appeared; (2) examine the degree to which those geometric designs of the horizontal and vertical profile; and (3) search positive safety and passive highway safety design of the point at which highway alignment factors initiate driving safety to facility or highway design.