• Title/Summary/Keyword: Gauss-Seidel method

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A Study on the Simultaneous Linear Equations by Computer (전자계산기에 의한 다원연립 일차방정식의 해법에 관한 연구)

  • 이정복
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.8 no.12
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    • pp.127-138
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    • 1985
  • There are several methods which have been presented up to now in solving the simultaneous linear equations by computer. They are Gaussian Elimination Method, Gauss-Jordan Method, Inverse matrix Method and Gauss-Seidel iterative Method. This paper is not only discussed in their mechanisms compared with their algorithms, depicted flow charts, but also calculated the numbers of arithmetic operations and comparisons in order to criticize their availability. Inverse Matrix Method among em is founded out the smallest in the number of arithmetic operation, but is not the shortest operation time. This paper also indicates the many problems in using these methods and propose the new method which is able to applicate to even small or middle size computers.

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Study on Reducing Processing Time for Restoration Method (영상신호 복원의 처리 시간단축을 위한 알고리즘에 대한 연구)

  • 권기홍
    • Journal of the Korea Computer Industry Society
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    • v.2 no.6
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    • pp.817-826
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    • 2001
  • In this paper, the method of processing a blurred noisy signal has been researched. The conventional method of processing signal has faults which are slow-convergence speed and long time-consuming process at the singular point and in the ill condition. There is the process, the Gauss-Seidel's method to remove these faults, but it takes too much time because it processes signal repeatedly. For overcoming the faults, this paper shows a signal process method which takes shorter than the Tikhnov-Miller's by comparing the Tikhnov-Miller's with proposed algorithm and accelerating convergence speed at the singular point in the ill condition. In this paper, the conventional process method and proposed optimal algorithm were used to get a standard image (256 * 256 * 8bits),and then the results are simulated and compared each other in order to examine the variance of MSE ( Mean-Square Error ) by the acceleration parameter in the proposed two dimensional signal procedures. The result of the signal process and the processing time was measured at all change of acceleration parameter in order to verify the effectiveness of the proposed algorithm.

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A Development of 3-D Numeric Model for the Confined Flow and Discharge under Sea Ground (해저 지중 피압유체의 흐름과 양수량 산출에 관한 3차원 수치모형의 개발)

  • Kim, Sang-Jun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.6
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    • pp.387-396
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    • 2010
  • A 3-D numeric model for the confined transient flow under sea ground have been developed. This is FDM model using Gauss-Seidel SOR (successive over-relaxation). This model shows the similar head distribution pattern to Theis analytic solution and MODFLOW simulation. The input flowrate to the aquifer and discharge of well have been compared. And it have been found that mass balance is influenced by the weight factor ${\alpha}$, i.e. fullyimplicit method (${\alpha}$=1) shows 5% error, but when ${\alpha}$ becomes to 0.5(Crank and Nicolson method) the mass balance becomes worse and the model result diverges. And the convergency of the model is not much different when $\lambda$ (over-relaxation factor)=0.8~1.5, but when $\lambda$>1.5, the model result diverges. The test-run shows that the well discharge becomes smaller when another well is near. This model can cover the isotropy$(Kx{\neq}Ky{\neq}Kz)$ and inhomogeneity, and can be used for the selection of well site, discharge calculation, and head prediction in case of the artificial recharge etc.

Efficient Iterative Physical Optics(IPO) Algorithms for Calculation of RCS (RCS 계산을 위한 효율적인 IPO 계산 방법)

  • Lee, Hyunsoo;Jung, Ki-Hwan;Chae, Dae-Young;Koh, Il-Suek
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.5
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    • pp.601-606
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    • 2014
  • The IPO(Iterative Physical Optics) method repeatedly applies the well-known PO(Physical Optics) approximation to calculate the scattered field by a large object. Thus, the IPO method can consider the multiple scattering in the object, which is ignored for the PO approximation. This kind of iteration can improve the final accuracy of the induced current on the scatterer, which can result in the enhancement of the accuracy of the RCS(Radar Cross Section) of the scatterer. Since the IPO method can not exactly but approximately solve the required integral equation, however, the convergence of the IPO solution can not be guaranteed. Hence, we apply the famous techniques used in the inversion of a matrix to the IPO method, which include Jacobi, Gauss-Seidel, SOR(Successive Over Relaxation) and Richardson methods. The proposed IPO methods can efficiently calculate the RCS of a large scatterer, and are numerically verified.

Geometric Effects on Pressure Distribution in Mechanical Face Seals (기계평면시일의 기하학적 형태가 압력분포에 미치는 영향에 관한 연구)

  • 김청균;이일권
    • Tribology and Lubricants
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    • v.5 no.2
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    • pp.48-54
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    • 1989
  • The effects of angular misalignment, coning and the temperature difference between the primary seal ring and the seal seat on the pressure distribution in mechanical face seals are analyzed. The modified Reynolds equation for the temperature dependent viscosity was solved by a finite difference approximation and Gauss-Seidel method. It is shown that the amplitude of pressure is significantly affected by the misalignment of the seals and a large temperature difference between the rotor and the stator.

Comparison of multigrid performance for higher order scheme with 5-point scheme

  • Han, Mun. S.;Kwak, Do Y.;Lee, Jun S.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.4 no.2
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    • pp.135-142
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    • 2000
  • We consider a multigrid algorithm for higher order finite difference scheme for the Poisson problem on rectangular domain. Several smoothers including Jacobi, Red-black Gauss-Seidel are tested and compared. Since higher order scheme gives much more accurate result then 5-point scheme, one may use small number of levels with higher order scheme and thus the overall cost is reduced quite a lot. The numerical experiment compares the two cases.

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Experimental and Theoretical Consideration for Flow Rate, Pressure Drop, and Permeate Flow in a Hollow Fiber Membrane (중공사 막을 따라 흐르는 순수한 물의 유량, 압력손실, 투과수에 대한 실험과 이론적 고찰)

  • Lee, Jung-Muk;Lee, Bomsock
    • Membrane Journal
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    • v.22 no.6
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    • pp.470-480
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    • 2012
  • In this study, for a linear tubular membrane with constant diameter the mass balance considering permeate velocity of the each unit length was established. On this basis, mathematical modelling of flows in a pipe was solved using nonlinear second order differential equations as well as steady-state equation. Since this equation is nonlinear, Gauss-Seidel method or another iteration method were used to solve the differential equations. Simulation algorithm for numerical solutions was presented. Also since the permeate flow is varied as operating condition, the solution of equations at each conditions using numerical integrations such as Simpson's rules was used. In order to analyze and compare simulation results, we have performed experiments using a hollow fiber membrane with almost identical tubular membrane. Comparison of theoretical and experimental results, pressure drop, flow rate, and permeate flow in a hollow fiber membrane, were illustrated.

Numerical Investigation of The Effect of External Stores on Tail Wing Surfaces of a Generic Fighter Aircraft (전투기 형상의 외부장착물이 꼬리날개에 미치는 영향에 대한 수치적 연구)

  • Kim, Min-Jae;Kwon, Oh-Joon;Kim, Ji-Hong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.3
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    • pp.211-219
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    • 2008
  • A three-dimensional inviscid flow solver has been developed based on unstructured meshes for the investigation of the effect of the external stores on the tail surfaces of a generic fighter aircraft. The numerical method is based on a vertex-centered finite-volume discretization and an implicit point Gauss-Seidel time integration. The calculations were made for a steady flow and the computed results were compared with experimental data to validate the flow solver. An unsteady time-accurate computation of the generic fighter aircraft with external stores at transonic flight conditions showed that the external stores cause unsteady loading on the horizontal tail surface due to the mutual interference between their wake and the horizontal tail surface. It was shown that downward deflection of the trailing edge flap significantly reduces the undesirable interference effect.

A Preconditioned Time Method for Efficient Calculation of Reactive Flow (예조건화 시간차분을 통한 화학반응유동의 효율적 계산)

  • Kim, Seong-Lyong;Jeung, In-Seuck;Choi, Jeong-Yeol
    • 한국연소학회:학술대회논문집
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    • 1999.10a
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    • pp.219-230
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    • 1999
  • The Equations of Chemical kinetics are very stiff, which forces the use of an implicit scheme. The problem of implicit scheme, however, is that the jacobian must be solved at each time step. In this paper, we examined the methodology that can be stable without full chemical jacobian, This method is derived by applying the different time steps to the chemical source term. And the lower triangular chemical jacobian is derived. This is called the preconditioned time differencing method and represents partial implicit method. We show that this method is more stable in chemical kinetics than the full implicit method and that this is more efficient in supersonic combustion problem than the full jacobian method with same accuracy.

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A Study for a Novel DistFlow Method in the Distribution System (배전계통에서의 새로운 DistFlow Method에 대한 연구)

  • Gwak, Do-Il;Kim, Jae-Eon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.49 no.7
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    • pp.365-368
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    • 2000
  • Traditionally, load flows have been calculated using the Gauss-Seidel and Newton-Raphson Method. DistFlow Method which is proposed by Wu and Baran is superior to the other two methods because it does not require the admittance matrix calculation to optimize the distribution system. This paper introduces a new alternative algorithm to the DistFlow Method which is slow and complex to find solutions as the number of lateral and sublateral increases. The proposed load flow method can construct System Jacobian easily. We can minimize the off-diagonal elements of the branch Jacobian and submatrices in the System Jacobian. Simulation results show that progressive performances of the proposed algorithm have a better convergence time.

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