• Title/Summary/Keyword: Vector space

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SPACE-LIKE SUBMANIFOLDS WITH CONSTANT SCALAR CURVATURE IN THE DE SITTER SPACES

  • Liu, Ximin
    • Journal of the Korean Mathematical Society
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    • v.38 no.1
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    • pp.135-146
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    • 2001
  • Let M(sup)n be a space-ike submanifold in a de Sitter space M(sub)p(sup)n+p (c) with constant scalar curvature. We firstly extend Cheng-Yau's Technique to higher codimensional cases. Then we study the rigidity problem for M(sup)n with parallel normalized mean curvature vector field.

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The Structure of Maximal Ideal Space of Certain Banach Algebras of Vector-valued Functions

  • Shokri, Abbas Ali;Shokri, Ali
    • Kyungpook Mathematical Journal
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    • v.54 no.2
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    • pp.189-195
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    • 2014
  • Let X be a compact metric space, B be a unital commutative Banach algebra and ${\alpha}{\in}(0,1]$. In this paper, we first define the vector-valued (B-valued) ${\alpha}$-Lipschitz operator algebra $Lip_{\alpha}$ (X, B) and then study its structure and characterize of its maximal ideal space.

HOMOGENEOUS REAL HYPERSURFACES IN A COMPLEX HYPERBOLIC SPACE WITH FOUR CONSTANT PRINCIPAL CURVATURES

  • Song, Hyunjung
    • Journal of the Chungcheong Mathematical Society
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    • v.21 no.1
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    • pp.29-48
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    • 2008
  • We deal with the classification problem of real hypersurfaces in a complex hyperbolic space. In order to classify real hypersurfaces in a complex hyperbolic space we characterize a real hypersurface M in $H_n(\mathbb{C})$ whose structure vector field is not principal. We also construct extrinsically homogeneous real hypersurfaces with four distinct curvatures and their structure vector fields are not principal.

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On vector Quasivariational-like inequality

  • Lee, Gue-Myung;Kim, Do-Sang;Lee, Byung-Soo
    • Bulletin of the Korean Mathematical Society
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    • v.33 no.1
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    • pp.45-55
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    • 1996
  • Recently, Giannessi [1] introduced a vector variational inequalityy for vector-valued functions in an Euclidean space. Since then, Chen et al. [2-6], Lee et al. [7], and Yang [8] have intensively studied vector variational inequalities for vector-valued functions in abstract spaces.

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The Phase Space Analysis of 3D Vector Fields (3차원 벡터 필드의 위상 공간 분석)

  • Jung, Il-Hong;Kim, Yong Soo
    • Journal of Digital Contents Society
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    • v.16 no.6
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    • pp.909-916
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    • 2015
  • This paper presents a method to display the 3D vector fields by analyzing phase space. This method is based on the connections between ordinary differential equations and the topology of vector fields. The phase space analysis should be geometric interpolation of an autonomous system of equation in the form of the phase space. Every solution of it system of equations corresponds not to a curve in a space, but the motion of a point along the curve. This analysis is the basis of this paper. This new method is required to decompose the hexahedral cell into five or six tetrahedral cells for 3D vector fields. The critical points can be easily found by solving a simple linear system for each tetrahedron. The tangent curves can be integrated by finding the intersection points of an integral curve traced out by the general solution of each tetrahedron and plane containing a face of the tetrahedron.

A NEW NON-MEASURABLE SET AS A VECTOR SPACE

  • Chung, Soon-Yeong
    • Communications of the Korean Mathematical Society
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    • v.21 no.3
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    • pp.429-432
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    • 2006
  • We use Cauchy's functional equation to construct a new non-measurable set which is a (vector) subspace of \mathbb{R}$ and is of a codimensiion 1, considering \mathbb{R}$, the set of real numbers, as a vector space over a field \mathbb{Q}$ of rational numbers. Moreover, we show that \mathbb{R}$ can be partitioned into a countable family of disjoint non-measurable subsets.

REAL HYPERSURFACES OF THE JACOBI OPERATOR WITH RESPECT TO THE STRUCTURE VECTOR FIELD IN A COMPLEX SPACE FORM

  • AHN, SEONG-SOO
    • Bulletin of the Korean Mathematical Society
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    • v.42 no.2
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    • pp.279-294
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    • 2005
  • We study a real hypersurface M satisfying $L_{\xi}S=0\;and\;R_{\xi}S=SR_{\xi}$ in a complex hyperbolic space $H_n\mathbb{C}$, where S is the Ricci tensor of type (1,1) on M, $L_{\xi}\;and\;R_{\xi}$ denotes the operator of the Lie derivative and the Jacobi operator with respect to the structure vector field e respectively.

Improved Space Vector Modulation Strategy for AC-DC Matrix Converters

  • Liu, Xiao;Zhang, Qingfan;Hou, Dianli;Wang, Siyao
    • Journal of Power Electronics
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    • v.13 no.4
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    • pp.647-655
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    • 2013
  • In this paper, an approach to reduce the common-mode voltage and to eliminate narrow pulse for implemented AC-DC matrix converters is presented. An improved space vector modulation (SVM) strategy is developed by replacing the zero space vectors with suitable pairs of active ones. Further, while considering the commutation time, the probability of narrow pulse in the conventional and proposed SVM methods are derived and compared. The advantages of the proposed scheme include: a 50% reduction in the peak value of the common-mode voltage; improved input and output performances; a reduction in the switching loss by a reduced number of switching commutations and a simplified implementation via software. Experimental results are presented to demonstrate the correctness of the theoretical analysis, as well as the feasibility of the proposed strategy.

Simulator Development for Evaluating Compensation Performance. of Active Power Filter using Three-Dimensional Space Current Co-ordinate (3차원(次元) 전류좌표(電流座標)에 의한 능동전력(能動電力)필터의 보상성능(補償性能) 평가(評價)를 위한 시뮬레이터 개발(開發))

  • Lim, Young-Choel;Jung, Young-Gook;Na, Suk-Hwan;Choi, Chan-Hak;Chang, Young-Hak
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.337-341
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    • 1994
  • This paper describes an effort to develop a simulator of Active Power Filter (APF) by three dimentional(3-D) space current co-ordinate. System current is represented by 3-D vector composed of three current components - active, reactive and distorted. %THD (%Total Harmonics Distortion) can be converted to height-angle of system current vector and power factor can be defined on 3-D space current co-ordinate without loss of generality. Current of APF and power system can be analyzed by 3-D visualization of current vector trajectory. So, the computer simulation results show that the proposed method by 3-D space current co-ordinate make up for disadvantages of performance evaluation on time / frequency domain.

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