• Title/Summary/Keyword: Singular Value Decomposition

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Comparison of Thresholding Techniques for SVD Coefficients in CT Perfusion Image Analysis (CT 관류 영상 해석에서의 SVD 계수 임계화 기법의 성능 비교)

  • Kim, Nak Hyun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.6
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    • pp.276-286
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    • 2013
  • SVD-based deconvolution algorithm has been known as the most effective technique for CT perfusion image analysis. In this algorithm, in order to reduce noise effects, SVD coefficients smaller than a certain threshold are removed. As the truncation threshold, either a fixed value or a variable threshold yielding a predetermined OI (oscillation index) is frequently employed. Each of these two thresholding methods has an advantage to the other either in accuracy or efficiency. In this paper, we propose a Monte Carlo simulation method to evaluate the accuracy of the two methods. An extension of the proposed method is presented as well to measure the effects of image smoothing on the accuracy of the thresholding methods. In this paper, after the simulation method is described, experimental results are presented using both simulated data and real CT images.

An Effective Selection of white Gaussian Noise Sub-band using Singular Value Decomposition (특이값 분해를 이용한 효율적인 백색가우시안 잡음대역 선정 방법)

  • Shin, Seung-Min;Kim, Young-Soo;Kim, Sang-Tae;Suk, Mi-Kyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.3A
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    • pp.272-280
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    • 2009
  • Measurement of the background radio noise is very important process being used in survey of radio noise environment, calculating the threshold level for the frequency occupancy measurement and so forth. First step of background radio noise measurement is to select the sample sub-band which is mostly dominated by the background white Gaussian noise (WGN) within the target band. The second step is to carry out the main measurement of radio noise on this selected sample sub-band for the representative value of the noise power. In this paper, a method for selection of sample sub-band for the effective background radio noise measurement using SVD is proposed under the assumption that background radio noise is WGN. The performance of the proposed method is compared with that of the APD method which is widely used for the same purpose. Simulation results are shown to demonstrate the high performance of the proposed method in comparison with the existing APD method.

Force/Moment Transmissionability Analysis of a Parallel Manipulator (병렬형 매니퓰레이터의 힘/모우멘트 전달특성에 관한 연구)

  • Ahn, Byoung-Joon;Hong, Keum-Shik
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.4
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    • pp.109-121
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    • 1996
  • This paper presents how the input forces along the prismatic joints of a parallel manipulator are transmitted to the upper platform. In order to consider force transmission and moment transmission seperately the Jacobian matrix for parallel manipulators is splitted into two parts. Magnitudes of input forces on the six actuators at a given manipulator configuration which generate maximum/minimum output force with no moment generated on the platform are obtained through the singular value decomposition of a matrix involving the Jacobian. Similarly the directions of the input forces to obtain only the rotation of the platform have been analyzed. Using the singular values a simple equation for the volume of ellipsoid which is a good tool for manipulability measure is provided. Obtained results could be useful in determinimg design parameters like radius of plaform, angles between joints, etc. Simulations are porvided.

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Improved Blind Cyclic Algorithm for Detection of Orthogonal Space-Time Block Codes

  • Le, Minh-Tuan;Pham, Van-Su;Mai, Linh;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.4 no.4
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    • pp.136-140
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    • 2006
  • In this paper, we consider the detection of orthogonal space-time block codes (OSTBCs) without channel state information (CSI) at the receiver. Based on the conventional blind cyclic decoder, we propose an enhanced blind cyclic decoder which has higher system performance than the conventional one. Furthermore, the proposed decoder offers low complexity since it does not require the computation of singular value decomposition.

TWO INEQUALITIES INVOLVING HADAMARD PRODUCTS OF POSITIVE SEMI-DEFINITE HERMITIAN MATRICES

  • Cao, Chong-Guang;Yang, Zhong-Peng;Xian Zhang
    • Journal of applied mathematics & informatics
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    • v.10 no.1_2
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    • pp.101-109
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    • 2002
  • We extend two inequalities involving Hadamard Products of Positive definite Hermitian matrices to positive semi-definite Hermitian matrices. Simultaneously, we also show the sufficient conditions for equalities to hold. Moreover, some other matrix inequalities are also obtained. Our results and methods we different from those which are obtained by S. Liu in [J. Math. Anal. Appl. 243:458-463(2000)] and B.-Y Wang et al in [Lin. Alg. Appl. 302-303: 163-172(1999)] .

MANCOVA Biplot

  • Choi Yong-Seok;Hyun Gee Hong;Jung Su Mi
    • Communications for Statistical Applications and Methods
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    • v.12 no.3
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    • pp.705-712
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    • 2005
  • Biplot is a graphical display of the rows and columns of an n${\times}$p data matrix. In particular, Gabriel (1995) suggested the MANOVA biplot using singular value decomposition (SVD) with the averages of response variables according to treatment groups. But his biplot may cause wrong results by disregarding them when there exist covariate effects. In this paper, we will provide the MANCOA biplot based on the SVD with the parameter estimates for MANCOVA model when there exist covariate effects.

Reliable $H_\infty$ control for descriptor systems with actuator failures (구동기 고장을 가지는 특이시스템의 신뢰 $H_\infty$ 제어)

  • Kim, Jong-Hae
    • Proceedings of the KIEE Conference
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    • 2003.11b
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    • pp.135-138
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    • 2003
  • In this paper, we provide a reliable few controller design method for descriptor systems satisfying asymptotic stability with $H_\infty$ norm bound and all actuator failures occurred within the pre-specified subset. The proper condition for the existence of a reliable $H_\infty$ controller and the controller design method are proposed by linear matrix inequality(LMI), Schur complements, and singular value decomposition. All solutions can be obtained simultaneously because the presented sufficient condition can be expressed as an LMI form.

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A Study on the System Identification of Cold Tandem Mills using the Subspace Method (부분 공간법을 이용한 연속 냉간 압연기의 시스템 규명에 관한 연구)

  • 장유신;김인수;이만형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.299-303
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    • 1995
  • This paper charcterizes dynamics of cold tandem minns, and constructs it state-space model of which are linear time invariant, using subspace method. Step responses particularly show the influence on mass transfer delay. Input-output data set are obtained form nonlinear differential equations including mass transfer delay and nonlinearity. It is shown that the identified state-apace model well approximates the original systems dynamics.

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Symbolic modeling of a 4-bar link flexible manipulator (4절기구를 가진 유연한 조작기의 기호적 모델링)

  • 이재원;주해호
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.559-564
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    • 1993
  • Nonlinear equation of motion of the flexible manipulator are derived by the Lagrangian method in symbolic form to better understand the structure of the dynamic model. The resulting equations of motion have a structure which is useful to reduce the number of terms calculated, to check correctness, or to extend the model to high order. A manipulator with a flexible 4 bar link mechanism is a constrained system whose equations are sensitive to numerical integration error. This constrained system is solved using the null space matrix of the constraint Jacobian matrix. Singular value decomposition is a stable algorithm to find the null space matrix.

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Constrained multivariable model based predictive control application to nonlinear boiler system (제약조건을 갖는 다변수 모델 예측 제어기의 비선형 보일러 시스템에 대한 적용)

  • 손원기;이명의;권오규
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.160-163
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    • 1996
  • This paper deals with MCMBPC(Multivariable Constrained Model Based Predictive Controller) for nonlinear boiler system with noise and disturbance. MCMBPC is designed by linear state space model obtained from some operating point of nonlinear boiler system and Kalman filter is used to estimate the state with noise and disturbance. The solution of optimization of the cost function constrained on input and/or output variables is achieved using quadratic programming, viz. singular value decomposition (SVD). The controller designed is shown to have excellent tracking performance via simulation applied to nonlinear dynamic drum boiler turbine model for 16OMW unit.

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