• Bulletin of the Korean Mathematical Society
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• v.30 no.1
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• pp.99-107
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• 1993

A vector space K with scalar product <.,.> is called a Krein space if it can be decomposed as a northogonal sum of a Hilbert space and an anti-space of a Hilbert space. The space K induces a Hilbert space $K_{J}$ in the inner product <.,.> $K_{J}$=<.,.>K, where $J^{2}$=I. the eigenspaces of J are denoted by $K^{+}$$_{J}$, which is a Hilbert space and $K^{-}$$_{J}$, which is an anti-space of a Hilbert space. Then the Krein space K is the orthogonal sum of $K^{+}$$_{J}$ and $K^{-}$$_{J}$. Such a decomposition of K is called a fundamental decomposition. In general, fundamental decompositions are not unique. The norm of the Hilbert space depends on the choice of a fundamental decomposion, but such norms are equivalent. The topology generated by these norms is called the strong or Mackey topology of K. It is used to define all topological notions on the Krein space K with respect to this topology. The Pontryagin index of a Krein space is the dimension of the antispace of a Hilbert space in any such decomposition. the dimension does not depend on the choice of orthogonal decomposition. A Krein space is called a Pontryagin space if it has finite Pontryagin index.dex.yagin index.dex.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1552-1557
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• 2015

The paper unleashes a new idea to arrive at reduced switch count topological structures configured in the form of a matrix for a cascaded Multi level inverter (CMLI). The theory encircles to minimize the number of switches involved in the conduction path and there from acclaim reduced input current distortion, lower switching losses and electromagnetic interference. The focus extends to standardize the number of power devices required for reaching different levels of output voltage from the same architecture. It includes appropriate pulse width modulation (PWM) strategy to generate firing pulses and ensure the desired operation of the power modules. The investigative study carries with it MATLAB based simulation and experimental results obtained using suitable prototypes to illustrate the viability of the proposed concept. The promising nature of the performance projects a new dimension in the use of single phase MLIs for renewable energy related applications.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.1911-1914
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• 2002

이 논문에서는 여러 가지 위상 관계 표현 방법을 바탕으로 3 차원 공간 객체들 간의 위상 관계를 여러 가지 방법으로 표현한다. 지리정보시스템 분야에서 공간 객체들 간의 위상 관계를 정의하는 것은 중요한 연구이다. 위상 관계를 표현하는 기존의 방법들은 2 차원 공간 객체를 대상으로 하고있다. 좀더 많은 공간 정보를 제공하기 위해, 3 차원 공간 데이터에 대한 위상 관계를 표현하고 정의한다. 또한, 4-intersection, 9-intersection, dimension extended, calculus-based 방법 등, 여러 연구에서 제시되었던 표현 방법을 사용하여 위상 관계를 정의한다.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.215-222
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• 1997

This paper deals with the problem of generating a uniform tetrahedral mesh which fills a 3-D space with the tetrahedra which are close to the equilateral tetrahedra as possible. This problem is particularly interesting in finite element modeling where a fat triangulation minimizes the error of an analysis. Fat triangulation is defined as a scheme for generating an equilateral triangulation as possible in a given dimension. In finite element modeling, there are many algorithms for generating a mesh in 2-D and 3-D. One of the difficulties in generating a mesh in 3-D is that a 3-D object can not be filled with uniform equilateral tetrahedra only regardless of the shape of the boundary. Fat triangulation in 3-D has been proved to be the one which fills a 3-D space with the tetrahedra which are close to the equilateral as possible. Topological and geometrical properties of the fat triangulation and its application to meshing algorithm are investigated.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1363-1366
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• 2003

기존 연구에서 3차원 공간 위상 관계 연산자를 정의하는 방법은 2차원 공간 위상 관계 정의를 위해 주로 사용되는 공간 교차 방법을 단순히 3차원으로 확장해서 정의하는 방식이다. 그러나 기존의 방법에 의해 정의된 3차원 위상 관계 연산자로는 3차원 데이터베이스를 이용한 실제 응용시스템에서 고려되어야 하는 특수한 위상 관계 분석을 수행하기 어렵다. 따라서 이 논문에서는 실제 응용에서 적용 될 수 있는 특수한 3차원 위상 관계를 정의하기 위하여 x,y 좌표와 z좌표를 분리해서 고려하는 새로운 기법을 제안한다. 또한 제안한 방법을 이용하여 새로운 3차원 공간 위상 관계 연산자들을 정의하고 구체적인 알고리즘을 제시한다.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.459-468
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• 1996

This paper considers the problem of realising a parallel EMG identifier used in FES (functional electrical stimulation) system on a fixed dimension transputer array. This involves using an identifiestion algorithm in the wavelet transform domain. This algorithm have suggested by the authors in a previous paper(6). The transputer serial links permit higtlly varied and economic network-type connections and the structure enables rapid topological reconfiguration. Analysing the results Showed that the Speed-UPS ranged from 1.82 to 3.44 With 2-4 transputers for corresponding model order, and from 1.82 to 3.97 with increasing the model orders when two and four transputers are used respectively.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.40-46
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• 2008

3D visualization of geological environments using remotely sensed data and the various sources of data provides new methodology to interpret geological observation data and analyze geo-information in earth science applications. It enables to understand spatio-temporal relationships and causal processes in the three-dimension, which would be difficult to identify without 3D representation. To build more realistic geological environments, which are useful to recognize spatial characteristics and relationships of geological objects, 3D modeling, topological analysis, and database should be coupled and taken into consideration for an integrated configuration of the system. In this study, a method for 3D visualization, extraction of geological data, storage and data management using remotely sensed data is proposed with the goal of providing a methodology to utilize dynamic spatio-temporal modeling and simulation in the three-dimension for geoscience and earth science applications.

• Spatial Information Research
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• v.13 no.2 s.33
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• pp.119-128
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• 2005

Most spatial data handled in GIS is two-dimensional. These two-dimensional data is established by selecting 2D aspects form 3D, or by projecting 3D onto 2D space. During this conversion, without user's intention, data are abstracted and omitted. This unwanted data loss causes disadvantages such as restrictingof the range of data application and describing inaccurate real world. Recently, three dimensional data is getting wide interests and demands. One of the examplesis Database Management System which can store and manage three dimensional spatial data. However, this DBMS does not support spatial query which is the essence of the database management system. So, various studies are needed in this field. This research designs spatial relationship that is defined in space database standard using the three-dimension space model. The spatial data model, which is used in this research, is the one defined in OGC for GMS3, and designing tool is DE-9IM based on Point-Set Topology blow as the best method for topological operation.

• International Journal of CAD/CAM
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• v.7 no.1
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• pp.71-80
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• 2007

Recently, feature-based solid modeling systems have been widely used in product design. However, for engineering analysis of a product model, an ed CAD model composed of mid-surfaces is desirable for conditions in which the ed model does not affect analysis result seriously. To meet this requirement, a variety of solid ion methods such as MAT (medial axis transformation) have been proposed to provide an ed CAE model from a solid design model. The algorithm of the MAT approach can be applied to any complicated solid model. However, additional work to trim and extend some parts of the result is required to obtain a practically useful CAE model because the inscribed sphere used in the MAT method generates insufficient surfaces with branches. On the other hand, the mid-surface ion approach supports a practical method for generating a two-dimensional ed model, even though it has difficulties in creating a mid-surface from some complicated parts. In this paper, we propose a dimension reduction approach on solid models based on the midsurface abstraction approach. This approach simplifies the solid model by abbreviating or removing trivial features first such as the fillet, mounting, or protrusion. The geometry of each face is replaced with mid-patches from the simplified model, and then unnecessary topological entities are deleted to generate a clean ed model. Also, additional work, such as extending and stitching mid-patches, completes the generation of a mid-surface model from the patches.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.29-37
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• 2004

This study analyze the architectural space in the aspect of the 'Raumplan' and 'Plan Libre'. These concepts based on the 'Raumplan versus Plan Libre' exhibition in Delft University, Netherlands. It is generally agreed that the concept of 'Plan Libre' in connection with Le Corbusie architecture and 'Raumplan' related to Adolf Loos's works. that exhibition contents was focused an extent of modem architecture. But, These concepts continually influence contemporary architecture and offer diverse vision in architecture. Therefore, this study focused on the analysis that look for common element in the space through the case study and space element connection in change of the values, technical growth. This Paper reveals that Adolf Loos's Raumplan is similar to Louis I. Kahn's 'Room' concept and Ando Tadao's centrifugal space composition method In the dwelling architecture. And the concept 'Plan Libre': non-definitive formal system and the elements : column, free form screening wall is revived as formal application of 3 dimension composition in architecture. and transfer lots, void, and linear space in Rem Koolhaas's urban design projects. These aspects is so called topology. This topological concept is an attempt in view of the space connection state rather than formative viewpoint.