• Title/Summary/Keyword: least-squares problem

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TLS (Total Least-Squares) within Gauss-Helmert Model: 3D Planar Fitting and Helmert Transformation of Geodetic Reference Frames (가우스-헬머트 모델 전최소제곱: 평면방정식과 측지좌표계 변환)

  • Bae, Tae-Suk;Hong, Chang-Ki;Lim, Soo-Hyeon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.4
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    • pp.315-324
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    • 2022
  • The conventional LESS (LEast-Squares Solution) is calculated under the assumption that there is no errors in independent variables. However, the coordinates of a point, either from traditional ground surveying such as slant distances, horizontal and/or vertical angles, or GNSS (Global Navigation Satellite System) positioning, cannot be determined independently (and the components are correlated each other). Therefore, the TLS (Total Least Squares) adjustment should be applied for all applications related to the coordinates. Many approaches were suggested in order to solve this problem, resulting in equivalent solutions except some restrictions. In this study, we calculated the normal vector of the 3D plane determined by the trace of the VLBI targets based on TLS within GHM (Gauss-Helmert Model). Another numerical test was conducted for the estimation of the Helmert transformation parameters. Since the errors in the horizontal components are very small compared to the radius of the circle, the final estimates are almost identical. However, the estimated variance components are significantly reduced as well as show a different characteristic depending on the target location. The Helmert transformation parameters are estimated more precisely compared to the conventional LESS case. Furthermore, the residuals can be predicted on both reference frames with much smaller magnitude (in absolute sense).

Sparse kernel classication using IRWLS procedure

  • Kim, Dae-Hak
    • Journal of the Korean Data and Information Science Society
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    • v.20 no.4
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    • pp.749-755
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    • 2009
  • Support vector classification (SVC) provides more complete description of the lin-ear and nonlinear relationships between input vectors and classifiers. In this paper. we propose the sparse kernel classifier to solve the optimization problem of classification with a modified hinge loss function and absolute loss function, which provides the efficient computation and the sparsity. We also introduce the generalized cross validation function to select the hyper-parameters which affects the classification performance of the proposed method. Experimental results are then presented which illustrate the performance of the proposed procedure for classification.

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Weighted LS-SVM Regression for Right Censored Data

  • Kim, Dae-Hak;Jeong, Hyeong-Chul
    • Communications for Statistical Applications and Methods
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    • v.13 no.3
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    • pp.765-776
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    • 2006
  • In this paper we propose an estimation method on the regression model with randomly censored observations of the training data set. The weighted least squares support vector machine regression is applied for the regression function estimation by incorporating the weights assessed upon each observation in the optimization problem. Numerical examples are given to show the performance of the proposed estimation method.

Image Reconstruction of Subspace Object Using Electrical Resistance Tomography

  • Boo, Chang-Jin;Kim, Ho-Chan;Lee, Yoon-Joon
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2480-2484
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    • 2005
  • Electrical resistance tomograpy (ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size, and resistivity of buried objects. In this paper, truncated least squares (TLS) is presented for the solution of the ERT image reconstruction. Results of numerical experiments in ERT solved by the TLS approach is presented and compared to that obtained by the Gauss-Newton method.

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Design of reduced-order controllers in two-degree-of-freedom control systems

  • Nakamura, T.;Obinata, G.;Inooka, H.
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10b
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    • pp.753-758
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    • 1988
  • In this paper, we propose a new method of designing a reduced-order controller for a linear discrete-time system. Firstly, we study a design problem for a two-degree-of-freedom control system with a feedforward controller. Secondly, in order to obtain a reduced-order controller, frequency-weighted least squares approximation problems are considered. Thirdly, we propose a synthesis procedure of a reduced-order controller. Finally, an example is given to illustrate the effectiveness of this proposed method.

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Large-sample comparisons of calibration procedures when both measurements are subject to error

  • Lee, Seung-Hoon;Yum, Bong-Jin
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1990.04a
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    • pp.254-262
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    • 1990
  • A predictive functional relationship model is presented for the calibration problem in which the standard as well as the nonstandard measurements are subject to error. For the estimation of the relationship between the two measurements, the ordinary least squares and maximum likelihood estimation methods are considered, while for the prediction of unknown standard measurementswe consider direct and inverse approaches. Relative performances of those calibration procedures are compared in terms of the asymptotic mean square error of prediction.

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A Study on System Identification using Haar Functions (Haar함수를 이용한 시스템 동정에 관한 연구)

  • 안두수;채영무;이명규
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.4
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    • pp.287-292
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    • 1987
  • This paper deals with applications of Haar functions to parameter identification of linear systems. It is first introuduced to a new operational matrix which relates Haar functions and their integrations. The matrix can be used to identify the parameters of unknown linear systems by a least squares estimation. And then, the state equation of given systems is transformed into a computationally convenient algebraic form. This approach provides a more efficient method for the system identification problem.

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Constrained Multichannel Adaptive FIR Beamforming Algorithm Based upon Least Squares Method (최소자승법을 이용한 Constrained Multichannel FIR 적응 빔 형성 알고리즘)

  • 김달수;신윤기;박의열
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.28A no.9
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    • pp.671-679
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    • 1991
  • In adaptive antenna, several models are known according to a prior knowledge about jammer signal. Among those, Frost model with contraint is generally used however it has the problem that convergence speed is slow and that stability is not good. To improve such problems, this paper proposes constrained NLMS algorithm using LS method. In addition, the result obtained by applying this algorithm to Duvall antenna model is compared with that of Frost model.

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TWO DIMENSIONAL VERSION OF LEAST SQUARES METHOD FOR DEBLURRING PROBLEMS

  • Kwon, SunJoo;Oh, SeYoung
    • Journal of the Chungcheong Mathematical Society
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    • v.24 no.4
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    • pp.895-903
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    • 2011
  • A two dimensional version of LSQR iterative algorithm which takes advantages of working solely with the 2-dimensional arrays is developed and applied to the image deblurring problem. The efficiency of the method comparing to the Fourier-based LSQR method and the 2-D version CGLS algorithm methods proposed by Hanson ([4]) is analyzed.

A FITTING OF PARABOLAS WITH MINIMIZING THE ORTHOGONAL DISTANCE

  • Kim, Ik-Sung
    • Journal of applied mathematics & informatics
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    • v.6 no.2
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    • pp.669-684
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    • 1999
  • We are interested in the problem of fitting a curve to a set of points in the plane in such a way that the sum of the squares of the orthogonal distances to given data points ins minimized. In[1] the prob-lem of fitting circles and ellipses was considered and numerically solved with general purpose methods. Especially in [2] H. Spath proposed a special purpose algorithm (Spath's ODF) for parabolas y-b=$c($\chi$-a)^2$ and for rotated ones. In this paper we present another parabola fitting algorithm which is slightly different from Spath's ODF. Our algorithm is mainly based on the steepest descent provedure with the view of en-suring the convergence of the corresponding quadratic function Q(u) to a local minimum. Numerical examples are given.