• Title/Summary/Keyword: Algebraic method

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Enumerate tropical algebraic curves (열대곡선 헤아리기)

  • Kim, Young Rock;Shin, Yong-Su
    • Journal for History of Mathematics
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    • v.30 no.3
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    • pp.185-199
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    • 2017
  • In tropical geometry, the sum of two numbers is defined as the minimum, and the multiplication as the sum. As a way to build tropical plane curves, we could use Newton polygons or amoebas. We study one method to convert the representation of an algebraic variety from an image of a rational map to the zero set of some multivariate polynomials. Mikhalkin proved that complex curves can be replaced by tropical curves, and induced a combination formula which counts the number of tropical curves in complex projective plane. In this paper, we present close examinations of this particular combination formula.

The equivalent second moment of area for the symmetrically tapered compression member (대칭형으로 taper진 압축재의 등가 단면2차모멘트)

  • 김상조;민영숙;김순철;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.04a
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    • pp.291-298
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    • 2001
  • When the compression members have the variable cross sections along their member axes, the determination of the elastic critical loads by classical methods becomes impossible and if possible involves complicated calculation only to obtain the approximate values of critical load. In this paper the elastic critical load coefficients of the tapered members with simply supported ends were determined by finite element method. And then the results were represented by simple algebraic equations of two parameters, a( =taper parameter) and m ( = sectional property parameter). One the basis of algebraic equations, the equivalent moment of inertia concept originally proposed by Bleich for a spesific case, are extended to the general cases.

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A New Accurate Equation for Estimating the Baseline for the Reversal Peak of a Cyclic Voltammogram

  • Oh, Sung-Hoon;Chang, Byoung-Yong
    • Journal of Electrochemical Science and Technology
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    • v.7 no.4
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    • pp.293-297
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    • 2016
  • Here we propose a new equation by which we can estimate the baseline for measuring the peak current of the reverse curve in a cyclic voltammogram. A similar equation already exists, but it is a linear algebraic equation that over-simplifies the voltammetric curve and may cause unpredictable errors when calculating the baseline. In our study, we find a quadratic algebraic equation that acceptably reflects the complexity included in a voltammetric curve. The equation is obtained from a laborious numerical analysis of cyclic voltammetry simulations using the finite element method, and not from the closed form of the mathematical equation. This equation is utilized to provide a virtual baseline current for the reverse peak current. We compare the results obtained using the old linear and new quadratic equations with the theoretical values in terms of errors to ascertain the degree to which accuracy is improved by the new equation. Finally, the equations are applied to practical cyclic voltammograms of ferricyanide in order to confirm the improved accuracy.

Optimal Control of Nonlinear Systems Using Block Pulse Functions (블럭펄스 함수를 이용한 비선형 시스템의 최적제어)

  • Jo, Yeong-Ho;An, Du-Su
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.3
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    • pp.111-116
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    • 2000
  • In this paper, we presented a new algebraic iterative algorithm for the optimal control of the nonlinear systems. The algorithm is based on tow steps. The first step transforms optimal control problem into a sequence of linear optimal control problem using the quasilinearization method. In the second step, TPB(two point boundary condition problem) is solved by algebraic equations instead of differential equations using BPF(block pulse functions). The proposed algorithm is simple and efficient in computation for the optimal control of nonlinear systems. In computer simulation, the algorithm was verified through the optimal control design of Van del pole system and Volterra Predatory-prey system.

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Analysis of Density Distribution for Unsteady Butane Flow Using Three-Dimensional Digital Speckle Tomography

  • Ko, Han-Seo;Park, Kwang-Hee;Kim, Yong-Jae
    • Journal of Mechanical Science and Technology
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    • v.18 no.7
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    • pp.1213-1221
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    • 2004
  • Transient and asymmetric density distributions have been investigated by three-dimensional digital speckle tomography. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and transient. The speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields have been reconstructed from the deflection angles by a real-time multiplicative algebraic reconstruction technique (MART).

A Computer Oriented Solution for the Fractional Boundary Value Problem with Fuzzy Parameters with Application to Singular Perturbed Problems

  • Asklany, Somia A.;Youssef, I.K.
    • International Journal of Computer Science & Network Security
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    • v.21 no.12
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    • pp.223-227
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    • 2021
  • A treatment based on the algebraic operations on fuzzy numbers is used to replace the fuzzy problem into an equivalent crisp one. The finite difference technique is used to replace the continuous boundary value problem (BVP) of arbitrary order 1<α≤2, with fuzzy boundary parameters into an equivalent crisp (algebraic or differential) system. Three numerical examples with different behaviors are considered to illustrate the treatment of the singular perturbed case with different fractional orders of the BVP (α=1.8, α=1.9) as well as the classical second order (α=2). The calculated fuzzy solutions are compared with the crisp solutions of the singular perturbed BVP using triangular membership function (r-cut representation in parametric form) for different values of the singular perturbed parameter (ε=0.8, ε=0.9, ε=1.0). Results are illustrated graphically for the different values of the included parameters.

SINGULAR INTEGRAL EQUATIONS AND UNDERDETERMINED SYSTEMS

  • KIM, SEKI
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.2 no.2
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    • pp.67-80
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    • 1998
  • In this paper the linear algebraic system obtained from a singular integral equation with variable coeffcients by a quadrature-collocation method is considered. We study this underdetermined system by means of the Moore Penrose generalized inverse. Convergence in compact subsets of [-1, 1] can be shown under some assumptions on the coeffcients of the equation.

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Reliability Expression for Complex System

  • Seong Cheol Lee
    • Communications for Statistical Applications and Methods
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    • v.3 no.3
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    • pp.125-133
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    • 1996
  • In this paper, we present a algebraic technique for computing system reliability for complex system. The method was originally developed as an aid to fault tree analysis but it applies to general problems of reliability assessment. A success expression which directly gives the reliability expression is formed and simplified by the procedure. Several algorithms and examples are illustrated.

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AMG-CG method for numerical analysis of high-rise structures on heterogeneous platforms with GPUs

  • Li, Zuohua;Shan, Qingfei;Ning, Jiafei;Li, Yu;Guo, Kaisheng;Teng, Jun
    • Computers and Concrete
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    • v.29 no.2
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    • pp.93-105
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    • 2022
  • The degrees of freedom (DOFs) of high-rise structures increase rapidly due to the need for refined analysis, which poses a challenge toward a computationally efficient method for numerical analysis of high-rise structures using the finite element method (FEM). This paper presented an efficient iterative method, an algebraic multigrid (AMG) with a Jacobi overrelaxation smoother preconditioned conjugate gradient method (AMG-CG) used for solving large-scale structural system equations running on heterogeneous platforms with parallel accelerator graphics processing units (GPUs) enabled. Furthermore, an AMG-CG FEM application framework was established for the numerical analysis of high-rise structures. In the proposed method, the coarsening method, the optimal relaxation coefficient of the JOR smoother, the smoothing times, and the solution method for the coarsest grid of an AMG preconditioner were investigated via several numerical benchmarks of high-rise structures. The accuracy and the efficiency of the proposed FEM application framework were compared using the mature software Abaqus, and there were speedups of up to 18.4x when using an NVIDIA K40C GPU hosted in a workstation. The results demonstrated that the proposed method could improve the computational efficiency of solving structural system equations, and the AMG-CG FEM application framework was inherently suitable for numerical analysis of high-rise structures.