• Title/Summary/Keyword: inversion problem

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On Line LS-SVM for Classification

  • Kim, Daehak;Oh, KwangSik;Shim, Jooyong
    • Communications for Statistical Applications and Methods
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    • v.10 no.2
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    • pp.595-601
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    • 2003
  • In this paper we propose an on line training method for classification based on least squares support vector machine. Proposed method enables the computation cost to be reduced and the training to be peformed incrementally, With the incremental formulation of an inverse matrix in optimization problem, current information and new input data can be used for building the new inverse matrix for the estimation of the optimal bias and Lagrange multipliers, so the large scale matrix inversion operation can be avoided. Numerical examples are included which indicate the performance of proposed algorithm.

Improvement of Alignment Accuracy in Electron Tomography

  • Jou, Hyeong-Tae;Lee, Sujeong;Kim, Han-Joon
    • Applied Microscopy
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    • v.43 no.1
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    • pp.1-8
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    • 2013
  • We developed an improved method for tilt series alignment with fiducial markers in electron tomography. Based on previous works regarding alignment, we adapted the Levenberg-Marquardt method to solve the nonlinear least squares problem by incorporating a new formula for the alignment model. We also suggested a new method to estimate the initial value for inversion with higher accuracy. The proposed approach was applied to geopolymers. A better alignment of the tilt series was achieved than that by IMOD S/W. The initial value estimation provided both stability and a good rate of convergence since the new method uses all marker positions, including those partly covering the tilt images.

Three-Dimensional Borehole Radar Modeling (3차원 시추공 레이다 모델링)

  • 예병주
    • Economic and Environmental Geology
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    • v.33 no.1
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    • pp.41-50
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    • 2000
  • Geo-radar survey which has the advantage of high-resolution and relatively fast survey has been widely used for engineering and environmental problems. Three-dimensional effects have to be considered in the interpretation of geo-radar for high-resolution. However, there exists a trouble on the analysis of the three dimensional effects. To solve this problem an efficient three dimension numerical modeling algorithm is needed. Numerical radar modeling in three dimensional case requires large memory and long calculating time. In this paper, a finite difference method time domain solution to Maxwell's equations for simulating electromagnetic wave propagation in three dimensional media was developed to make economic algorithm which requires smaller memory and shorter calculating time. And in using boundary condition Liao absorption boundary. The numerical result of cross-hole radar survey for tunnel is compared with real data. The two results are well matched. To prove application to three dimensional analysis, the results with variation of tunnel's incident angle to survey cross-section and the result when the tunnel is parallel to the cross-section were examined. This algorithm is useful in various geo-radar survey and can give basic data to develop dat processing and inversion program.

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The Optimization Method of Symmetrical Building Plan Using Point Group Theory (포인트그룹 이론을 이용한 대칭적 건물 평면형태의 최적대안 결정방안)

  • 진경일
    • Korean Institute of Interior Design Journal
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    • no.38
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    • pp.75-82
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    • 2003
  • The symmetry is general geometric design principal in contemporary architecture shape. But, Symmetry sometimes easily causes unreasonable design. In some reason, two of symmetric units in the apartment, one side of unit have very reasonable plan and arrangement but opposite side unit nay not. For example, if the kitchen on right unit had right-handed arrangement, the symmetrical other would have left-handed kitchen arrangement. In addition to this, if each house unit has the same plan but different direction, each unit has different usage or affects the residents' life pattern. Nevertheless, Architects use only one unit plan to design public housing development by using symmetric operator (mirror, proper rotation, inversion center) at their option. This study suggests that using group theory and mathematical matrix rather than designer's discretion can solve this symmetry problem clearly. And, this study analysis the merits and demerits between each symmetrical pair of unit plan shapes by using mathematical point group theory and matrix.

Effect of heat source and gravity on a fractional order fiber reinforced thermoelastic medium

  • Jain, Kavita;Kalkal, Kapil Kumar;Deswal, Sunita
    • Structural Engineering and Mechanics
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    • v.68 no.2
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    • pp.215-226
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    • 2018
  • In this article, the theory of fractional order two temperature generalized thermoelasticity is employed to study the wave propagation in a fiber reinforced anisotropic thermoelastic half space in the presence of moving internal heat source. The whole space is assumed to be under the influence of gravity. The surface of the half-space is subjected to an inclined load. Laplace and Fourier transform techniques are employed to solve the problem. Expressions for different field variables in the physical domain are derived by the application of numerical inversion technique. Physical fields are presented graphically to study the effects of gravity and heat source. Effects of time, reinforcement, fractional parameter and inclination of load have also been reported. Results of some earlier workers have been deduced from the present analysis.

Influence of various sources in micropolar thermoelastic medium with voids

  • Kumar, Rajneesh;Ailawalia, Praveen
    • Structural Engineering and Mechanics
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    • v.31 no.6
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    • pp.717-735
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    • 2009
  • The present problem is concerned with the study of deformation of micropolar thermoelastic medium with voids under the influence of various sources acting on the plane surface. The analytic expressions of displacement components, force stress, couple stress, change in volume fraction field and temperature distribution are obtained in the transformed domain for Lord-Shulman (L-S) theory of thermoelasticity after applying the integral transforms. A numerical inversion technique has been applied to obtain the solution in the physical domain. The numerical results are presented graphically. Some useful particular cases have also been deduced.

Thermomechanical deformation in porous generalized thermoelastic body with variable material properties

  • Kumar, Rajneesh;Devi, Savita
    • Structural Engineering and Mechanics
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    • v.34 no.3
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    • pp.285-300
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    • 2010
  • The two-dimensional deformation of a homogeneous, isotropic thermoelastic half-space with voids with variable modulus of elasticity and thermal conductivity subjected to thermomechanical boundary conditions has been investigated. The formulation is applied to the coupled theory(CT) as well as generalized theories: Lord and Shulman theory with one relaxation time(LS), Green and Lindsay theory with two relaxation times(GL) Chandrasekharaiah and Tzou theory with dual phase lag(C-T) of thermoelasticity. The Laplace and Fourier transforms techniques are used to solve the problem. As an application, concentrated/uniformly distributed mechanical or thermal sources have been considered to illustrate the utility of the approach. The integral transforms have been inverted by using a numerical inversion technique to obtain the components of displacement, stress, changes in volume fraction field and temperature distribution in the physical domain. The effect of dependence of modulus of elasticity on the components of stress, changes in volume fraction field and temperature distribution are illustrated graphically for a specific model. Different special cases are also deduced.

A FREQUENCY-DOMAIN METE10D FOR FINITE ELEMENT SOLUTIONS OF PARABOLIC PROBLEMS

  • Lee, Chang-Ock;Lee, Jongwoo;Sheen, Dongwoo
    • Bulletin of the Korean Mathematical Society
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    • v.39 no.4
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    • pp.589-606
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    • 2002
  • We introduce and analyze a frequency-domain method for parabolic partial differential equations. The method is naturally parallelizable. After taking the Fourier transformation of given equations in the space-time domain into the space-frequency domain, we propose to solve an indefinite, complex elliptic problem for each frequency. Fourier inversion will then recover the solution in the space-time domain. Existence and uniqueness as well as error estimates are given. Fourier invertibility is also examined. Numerical experiments are presented.

Hierarchical Optimal Control of Nonlinear System using Haar Function (하알 함수를 이용한 비선형계의 계층별 최적제어)

  • Park, Jung-Ho;Cho, Young-Ho;Shin, Seung-Kwon;Chung, Je-Wook;Shim, Jae-Sun;Ahn, Doo-Soo
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.485-487
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    • 1999
  • We propose the algorithm with which one can solve the problem of the two-level hierarchical optimal control of nonlinear systems by repeatedly updating the state vectors using the haar function and Picard's iteration methods. Using the simple operation of the coefficient vectors from the fast haar transformation in the upper level and applying that vectors to Picard iteration methods in the independently lower level allow us to obtain the another method except the inversion matrix operation of the high dimention and the kronecker product in the optimal control algorithm.

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An Efficient Inverse Kinematics Solution Method for the 6 Axes Robot with Offest Wrist (손목오프셋을 갖는 6축 로봇을 위한 효과적인 역기구학 해 방법)

  • 범진환;임생기;손명현
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.6
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    • pp.1421-1429
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    • 1994
  • An algorithm is developed for solving the inverse kinematic problem of a 6-degree-of-freedom robot with a wrist offset for which the closed form inverse solutions are not obtainable, but knowledge of one joint variable allows closed form solutions of the remaining joint variables. The algorithm does not require Forward Kinematics nor Jacobian but uses the implicit kinematic relationships between joint variables and the given hand position. An iterative back substitution method is used to solve the inversion and the optimal conditions of the convergence are incoporated. An example is given to illustrate the concepts, the solution procedure and its convergency.