• Title/Summary/Keyword: Eigenvalue Decomposition

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Adaptive Eigenvalue Decomposition Approach to Blind Channel Identification

  • Byun, Eul-Chool;Ahn, Kyung-Seung;Baik, Heung-Ki
    • Proceedings of the IEEK Conference
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    • 2001.06a
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    • pp.317-320
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    • 2001
  • Blind adaptive channel identification of communication channels is a problem of important current theoretical and practical concerns. Recently proposed solutions for this problem exploit the diversity induced by antenna array or time oversampling leading to the so-called, second order statistics techniques. And adaptive blind channel identification techniques based on a off-line least-squares approach have been proposed. In this paper, a new approach is proposed that is based on eigenvalue decomposition. And the eigenvector corresponding to the minimum eigenvalue of the covariance matrix of the received signals contains the channel impulse response. And we present a adaptive algorithm to solve this problem. The performance of the proposed technique is evaluated over real measured channel and is compared to existing algorithms.

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Vector decomposition of the evolution equations of the conformation tensor of Maxwellian fluids

  • Cho, Kwang-Soo
    • Korea-Australia Rheology Journal
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    • v.21 no.2
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    • pp.143-146
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    • 2009
  • Breakthrough of high Weisenberg number problem is related with keeping the positive definiteness of the conformation tensor in numerical procedures. In this paper, we suggest a simple method to preserve the positive definiteness by use of vector decomposition of the conformation tensor which does not require eigenvalue problem. We also derive the constitutive equation of tensor-logarithmic transform in simpler way than that of Fattal and Kupferman and discuss the comparison between the vector decomposition and tensor-logarithmic transformation.

Image Reconstruction of Eigenvalue of Diffusion Principal Axis Using Diffusion Tensor Imaging (확산텐서영상을 이용한 확산 주축의 고유치 영상 재구성)

  • Kim, In-Seong;Kim, Joo-Hyun;Yeon, Gun;Suh, Kyung-Jin;Yoo, Don-Sik;Kang, Duk-Sik;Bae, Sung-Jin;Chang, Yong-Min
    • Investigative Magnetic Resonance Imaging
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    • v.11 no.2
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    • pp.110-118
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    • 2007
  • Purpose: The objective of this work to construct eigenvalue maps that have information of magnitude of three primary diffusion directions using diffusion tensor images. Materials and Methods: To construct eigenvalue maps, we used a 3.0T MRI scanner. We also compared the Moore-Penrose pseudo-inverse matrix method and the SVD (single value decomposition) method to calculate magnitude of three primary diffusion directions. Eigenvalue maps were constructed by calculating of magnitude of three primary diffusion directions. We did investigate the relationship between eigenvalue maps and fractional anisotropy map. Results: Using Diffusion Tensor Images by diffusion tensor imaging sequence, we did construct eigenvalue maps of three primary diffusion directions. Comparison between eigenvalue maps and Fractional Anisotropy map shows what is difference of Fractional Anisotropy value in brain anatomy. Furthermore, through the simulation of variable eigenvalues, we confirmed changes of Fractional Anisotropy values by variable eigenvalues. And Fractional anisotropy was not determined by magnitude of each primary diffusion direction, but it was determined by combination of each primary diffusion direction. Conclusion: By construction of eigenvalue maps, we can confirm what is the reason of fractional anisotropy variation by measurement the magnitude of three primary diffusion directions on lesion of brain white matter, using eigenvalue maps and fractional anisotropy map.

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An Adaptive Time Delay Estimation Method Based on Canonical Correlation Analysis (정준형 상관 분석을 이용한 적응 시간 지연 추정에 관한 연구)

  • Lim, Jun-Seok;Hong, Wooyoung
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.6
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    • pp.548-555
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    • 2013
  • The localization of sources has a numerous number of applications. To estimate the position of sources, the relative delay between two or more received signals for the direct signal must be determined. Although the generalized cross-correlation method is the most popular technique, an approach based on eigenvalue decomposition (EVD) is also popular one, which utilizes an eigenvector of the minimum eigenvalue. The performance of the eigenvalue decomposition (EVD) based method degrades in the low SNR and the correlated environments, because it is difficult to select a single eigenvector for the minimum eigenvalue. In this paper, we propose a new adaptive algorithm based on Canonical Correlation Analysis (CCA) in order to extend the operation range to the lower SNR and the correlation environments. The proposed algorithm uses the eigenvector corresponding to the maximum eigenvalue in the generalized eigenvalue decomposition (GEVD). The estimated eigenvector contains all the information that we need for time delay estimation. We have performed simulations with uncorrelated and correlated noise for several SNRs, showing that the CCA based algorithm can estimate the time delays more accurately than the adaptive EVD algorithm.

A Form-finding of Planar Tensegrity Structures

  • Lee, Sang Jin
    • Architectural research
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    • v.14 no.4
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    • pp.143-152
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    • 2012
  • A form-finding procedure is presented for planar tensegrity structures. Notably, a simple decision criteria is proposed to select the desirable candidate position vector from the unitary matrix produced by the eigenvalue decomposition of force density matrix. The soundness of the candidate position vector guarantees faster convergence and produces a desirable form of tensegrity without any member having zero-length. Several numerical examples are provided to demonstrate the capability of the proposed form-finding process.

Interference Cancellation for QO-STBC with EVD (EVD기법을 이용한 QO-STBC의 간섭 제거)

  • Kim, Dong Jin
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.6
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    • pp.46-52
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    • 2016
  • Quasi-Orthogonal STBC (QO-STBC) scheme is proposed conventionally achieving approximate full rate and full diversity in more than 3 transmit antenna and open-loop environmen.. But, conventional QO-STBC has disadvantage that performance degradation by interference terms of detection matrix and high decoding complexity. Recently, this interference cancellation scheme of low decoding complexity by multiplying specific rotation matrix is proposed. We propose more general interference cancellation scheme by using EVD(Eigenvalue Decompostion).

A Refined Semi-Analytic Sensitivity Study Based on the Mode Decomposition and Neumann Series Expansion in Eigenvalue Problem(II) - Eigenvalue Problem - (강체모드분리와 급수전개를 통한 고유치 문제에서의 준해석적 설계 민감도 개선에 관한 연구(II) -동적 문제 -)

  • Kim, Hyun-Gi;Cho, Maeng-Hyo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.4
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    • pp.593-600
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    • 2003
  • Structural optimization often requires the evaluation of design sensitivities. The Semi Analytic Method(SAM) fur computing sensitivity is popular in shape optimization because this method has several advantages. But when relatively large rigid body motions are identified for individual elements. the SAM shows severe inaccuracy. In this study, the improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes. Moreover. the error of the SAM caused by numerical difference scheme is alleviated by using a series approximation for the sensitivity derivatives and considering the higher order terms. Finally the present study shows that the refined SAM including the iterative method improves the results of sensitivity analysis in dynamic problems.

Characteristics of Jacket Matrix for Communication Signal Processing (통신신호처리를 위한 Jacket 행렬의 특성(特性))

  • Lee, Moon-Ho;Kim, Jeong-Su
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.21 no.2
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    • pp.103-109
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    • 2021
  • About the orthogonal Hadamard matrix announced by Hadamard in France in 1893, Professor Moon Ho Lee newly defined it as Center Weight Hadamard in 1989 and announced it, and discovered the Jacket matrix in 1998. The Jacket matrix is a generalization of the Hadamard matrix. In this paper, we propose a method of obtaining the Symmetric Jacket matrix, analyzing important properties and patterns, and obtaining the Jacket matrix's determinant and Eigenvalue, and proved it using Eigen decomposition. These calculations are useful for signal processing and orthogonal code design. To analyze the matrix system, compare it with DFT, DCT, Hadamard, and Jacket matrix. In the symmetric matrix of Galois Field, the element-wise inverse relationship of the Jacket matrix was mathematically proved and the orthogonal property AB=I relationship was derived.

A REFINED SEMI-ANALYTIC DESIGN SENSITIVITIES BASED ON MODE DECOMPOSITION AND NEUMANN SERIES IN REDUCED SYSTEM (축소모델에서 강체모드 분리와 급수전개를 통한 준해석적 민감도 계산 방법)

  • Kim, Hyun-Gi;Cho, Maeng-Hyo
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.491-496
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    • 2003
  • In sensitivity analysis, semi-analytical method(SAM) reveals severe inaccuracy problem when relatively large rigid body motions are identified for individual elements. Recently such errors of SAM resulted by the finite difference scheme have been improved by the separation of rigid body mode. But the eigenvalue should be obtained first before the sensitivity analysis is performed and it takes much time in the case that large system is considered. In the present study, by constructing a reduced one from the original system, iterative method combined with mode decomposition technique is proposed to compute reliable semi-analytical design sensitivities. The sensitivity analysis is performed by the eigenvector acquired from the reduced system. The error of SAM caused by difference scheme is alleviated by Von Neumann series approximation.

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