• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.970-975
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• 2002

We suggests an effective method to construct time-varying C-obstacles in the 3-dimensional configuration space (C-space) using free arc. The concept of free arc was defined mathematically and the procedure to find free arc in the case off-dimensional C-space was derived in [1]. We showed that time-varying C-obstacles can be constructed efficiently using this concept, and presented simulation results for two SCARA robot manipulators to verify the efficacy of the proposed approach. In this paper, extensions of this approach to the 3-dimensional C-space is introduced since nearly all industrial manipulators are reasonably treated ill the too or three dimensional C-space f3r collision avoidance problem The free arc concept is summarized briefly and the method to find lice arc in the 3-dimensional f-space is explained. To show that this approach enables us to solve a practical collision avoidance problem simulation results f3r two PUMA robot manipulators are presented.

• Bulletin of the Korean Mathematical Society
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• v.50 no.4
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• pp.1099-1108
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• 2013

We define the Mannheim curve in a 3-dimensional Riemannian manifold, which is a generalization of the Mannheim curve in Euclidean space. In particular, we study the Mannheim curves and their partner curves in 3-dimensional space forms.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.67-70
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• 1991

When analyzing field or optimizing the shape of electrode in three dimensional space by using the surface charge method, we need to divide finely the surface of electrode into surface element like triangle or rectangle. In this case, there exist any variables in field analysis or field optimization. In particular, smoothness on the surface of optimized shape is not good. Recently, A paper is published where introducing NURB curve to field analysis and field optimization about two dimensional space model and axial symmetric three dimensional space model results in reduced variables, enhenced accuracy and improved smoothness. NURB curve has some useful properties like continuity, controllability and locality. Therefore in this paper, in order to improve the demerits of the established optimization method for three dimensional space models, the NURB surface that has same properties in common with NURB curve is used to analyze and optimize simple model.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.5
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• pp.455-465
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• 2020

As cities continue to expand and additional underground structures are constructed, a policy is being planned to expand addresses, which are national framework data. In this study, the application scope of a proposed 3D (three-dimensional) mixed-use complex space for assigning 3D addresses was defined, based on past research on 3D address systems and by analyzing related laws. Underpass shopping malls, underground walkways (excluding underground shopping malls), and 3D mixed-use transfer centers with a gross floor area of 2,000㎡ or more are connected with each space by underground walkways or public paths. In addition, the detailed space corresponding to the public space of the 3D mixed-use complex space was presented and distinguished from the space to which the detailed address is assigned. The criteria for setting the road section were presented based on the intermediate space, which is a characteristic of 3D mixed-use complex spaces. The proposed criteria were applied to the Express Bus Terminal station (3D mixed-use transfer center) and COEX mall (underpass shopping malls). Thus, the road section was set for an unfamiliar 3D mixed-use complex space. However, by applying the proposed criteria to various 3D mixed-use complex spaces, additional and detailed criteria for different cases should be prepared.

• Korean Institute of Interior Design Journal
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• v.16 no.5
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• pp.38-46
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• 2007

In the late 1970s, the method of quantitative and scientific space structural analysis based on graph theory was introduced to the process of space design, which arranges design and functional elements, as relying heavily on intuition could produce errors due to unverified experiences and prejudices of the designer. As the method of space analysis is complex and hard to express visually and requires repetitive operations, it was discussed theoretically only. However, with the development of computer performance and graphic in recent years, visualization became possible. But the method of visual structural analysis of space is at the level of two dimensions and it is not easy to get accurate data when it is applied to limited three dimensional space such as an interior space. For the visual structural analysis of space, this study presents 4 indices including visibility volume level, pure visibility connection frequency, effective visibility connection frequency, and path visibility connection frequency. This study also presents space division using three dimensional arrangement rather than the existing vector operation method and raytracing algorithm at the lattice constant. Based on this, an analysis tool for the visible regions of three dimensional space that is capable of evaluating at multiple points by using three dimensional game engine and presentation tool that allows the analyzer to interpret the data effectively is made. It is applied to 2 prototype models by displacing Z axis, and the results are compared with UCL Depthmap to verify the validity of data and evaluate its usefulness as a multidimensional, multi-view space analysis tool.

• Communications of the Korean Mathematical Society
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• v.35 no.3
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• pp.967-977
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• 2020

In this article, we find the necessary and sufficient condition for a proper biharmonic Frenet curve in the Lorentzian Sasakian space forms 𝓜³₁(H) except the case constant curvature -1. Next, we find that for a slant curve in a 3-dimensional Sasakian Lorentzian manifold, its ratio of "geodesic curvature" and "geodesic torsion -1" is a constant. We show that a proper biharmonic Frenet curve is a slant pseudo-helix with 𝜅² - 𝜏² = -1 + 𝜀₁(H + 1)𝜂(B)² in the Lorentzian Sasakian space forms x1D4DC³₁(H) except the case constant curvature -1. As example, we classify proper biharmonic Frenet curves in 3-dimensional Lorentzian Heisenberg space, that is a slant pseudo-helix.

• Journal of architectural history
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• v.15 no.3
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• pp.27-42
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• 2006

Many contemporary architectural avant gardes tend to use painting as a medium to create architecture which goes beyond the rationalized spatial conception of modem architecture represented by perspectivism. They produce non perspective drawings to represent spatial Ideas, and expand it through poetic imagination to create an unexpected architectural form and space. This paper attempts to analyze the historical origin and background of dominance of drawing in the production of architecture. It was with the invention of perspective that architectural representation became important tool for architectural production. Thereafter, drawing was considered prior to actual building and architecture was considered a three dimensional realization of two dimensional drawing. Modernist avant gardes such as Cubism shattered the rationalized pictorial space of perspective and found a new pictorial space. They tried to extend it to three dimensional space through parallel projection largely based on the Hildebrand's theory of pure visibility. However, due to the ambiguity of the position of the viewing subject, their attempts could not succeed in creating a new architecture. The new architectural avant garde of the 70's rediscovered the early 20th century avant gardes in their attempt to create a new architecture which can register the fragmented spatial condition of contemporary society, and used painting as a medium to create architecture. Their difference from the early avant gardes was that they used poetic imagination rather than parallel projection in the process of projecting three dimensional space and form from the painting. However, their architecture cannot escape the scopic field of perspectivism in that they rely on the picture plane and the distance between object and viewing subject. Therefore, I conclude that in order to create architecture which goes beyond the rationalized space of modern architecture, it is necessary to resort to other tradition of modern architecture than visual one.

• Journal of the Korean Mathematical Society
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• v.55 no.1
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• pp.59-71
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• 2018

In the present paper, we study and classify factorable surfaces in a 3-dimensional isotropic space with constant isotropic Gaussian (K) and mean curvature (H). We provide a non-existence result relating to such surfaces satisfying ${\frac{H}{K}}=const$. Several examples are also illustrated.

• Communications of the Korean Mathematical Society
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• v.16 no.2
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• pp.253-263
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• 2001

Niebergall and Ryan posed some open questions on 3-dimensional real hypersurfaces in complex space forms. In this paper we give affirmative answers to such kind of questions.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.270-271
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• 2008

The positioning technology for a moving object is an important and essential component of ubiquitous communication computing environment and applications, for which Radio Frequency IDentification Identification(RFID) is has been considered as also a core technology for ubiquitous wireless communication. RFID-based positioning system calculates the position of moving object based on k-nearest neighbor(k-nn) algorithm using detected k-tags which have known coordinates and k can be determined according to the detection range of RFID system. In this paper, RFID-based positioning system determines the position of moving object not using weight factor which depends on received signal strength but assuming that tags within the detection range always operate and have same weight value. Because the latter system is much more economical than the former one. The geometries of tags were determined with considerations in huge buildings like office buildings, shopping malls and warehouses, so they were determined as the line in 1-Dimensional space, the square in 2-Dimensional space and the cubic in 3-Dimensional space. In 1-Dimensional space, the optimal detection range is determined as 125% of the tag spacing distance through the analytical and numerical approach. Here, the analytical approach means a mathematical proof and the numerical approach means a simulation using matlab. But the analytical approach is very difficult in 2- and 3-Dimensional space, so through the numerical approach, the optimal detection range is determined as 134% of the tag spacing distance in 2-Dimensional space and 143% of the tag spacing distance in 3-Dimensional space. This result can be used as a fundamental study for designing RFID-based positioning system.