• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.16 no.1
• /
• pp.69-76
• /
• 2003

Low-tension cables have been increasingly used in recent years due to deep-sea developments and the advent of synthetic cables. In the case of low-tension cables, large displacements may happen due to relatively small restoring forces of tension and thus the effects of fluid and geometric non-linearities and bending stiffness. A Fortran program is developed by employing a finite difference method. In the algorithm, an implicit time integration and Newton-Raphson iteration are adopted. For the calculation of huge size of matrices, block tri-diagonal matrix method is applied, which is much faster than the well-known Gauss-Jordan method in two point boundary value problems. Some case studies are carried out and the results of numerical simulations are compared with a in-house program of WHOI Cable with good agreements.

• Journal of Electrical Engineering and Technology
• /
• v.3 no.3
• /
• pp.385-390
• /
• 2008

For taking account of the two-dimensional magnetic properties of a grain-oriented electrical steel sheet, the effective anisotropic tensor reluctivity is examined, and a computationally efficient algorithm is suggested by using the response surface method to model the two-dimensional magnetic properties. It is shown that the reconstructed two-dimensional magnetic properties are fairly effective to stabilize the convergence characteristics of the Newton-Raphson iteration in the nonlinear magnetic field analysis.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.2
• /
• pp.73-78
• /
• 2005

The management of technological systems will become increasingly complex. Safe and reliable software operation is a significant requirement for many types of system. So, with software fault tolerance, we want to prevent failures by tolerating faults whose occurrences are known when errors are detected. This paper presents a fault location algorithm for single-phase-to-ground faults on the teed circuit of a parallel transmission line using software fault tolerance technique. To find the fault location of transmission line, we have to solve the 3rd order transmission line equation. A significant improvement in the identification of the fault location was accomplished using the N-Version Programming (NVP) design paradigm. The delivered new algorithm has been tested with the simulation data obtained from the versatile EMTP simulator.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.43-45
• /
• 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.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.04a
• /
• pp.167-172
• /
• 1998

An algorithm of Thermal-elastohydrodynamic lubrication analysis for the piston ring is developed. This algorithm contains cavitation boundary condition so it automatically satisfies conservation of mass. 1-D Reynolds equation and 2-D energy equation are solved simultaneously by using Gauss-Jordan method and Newton-Raphson method. Minimum film thickness and friction force are calculated for 1 cycle. There is little difference between the results caculated by isothermal rigid and EHL analysis in entire cycle. In the results of THL, shear heating effect and temperature boundary condition affect the minimum film thickness and friction force prediction. The minimum film thickness and the friction force calculated by THL are lower than those caculated using isothermal assumption.

• Smart Structures and Systems
• /
• v.19 no.4
• /
• pp.403-413
• /
• 2017

The present article encompasses a nonlinear finite element (FE) and genetic algorithm (GA) based optimal vibration energy harvesting from nonprismatic piezo-laminated cantilever beams. Three cases of cross section profiles (such as linear, parabolic and cubic) are modelled to analyse the geometric nonlinear effects on the output responses such as displacement, voltage, and power. The simultaneous effects of taper ratios (such as breadth and height taper) on the output power are also studied. The FE based nonlinear dynamic equation of motion has been solved by an implicit integration method (i.e., Newmark method in conjunction with the Newton-Raphson method). Besides this, a real coded GA based constrained optimization scheme has also been proposed to determine the best set of design variables for optimal harvesting of power within the safe limits of beam stress and PZT breakdown voltage.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.541-547
• /
• 2000

This paper presents the closed-form forward kinematics of the 6-6 Stewart platform of planar base and moving platform. Based on algebraic elimination method and with one extra linear sensor, it first derives an 8th-degree univariate equation and then finds tentative solution sets out of which the actual solution is to be selected. In order to provide more exact solution despite the error between measured sensor value and the theoretical one, a correction method is also used. The overall procedure requires so little computation time that it can be efficiently used for realtime applications. In addition, unlike the iterative schemes e.g. Newton-Raphson, the algorithm does not require initial estimates of solution and is free of the problems that it does not converge to actual solution within limited time. The presented method has been implemented in C language and a numerical example is given to confirm the effectiveness and accuracy of the developed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.49 no.7
• /
• pp.365-368
• /
• 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.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.60.4-60
• /
• 2001

Electrical impedance tomograpy (EIT) determines the resistivity distribution inside an inhomogeneous target by means of voltage and current measurements conducted at the target boundary. In this paper, a genetic algorithm (GA) approach is proposed for the solution of the EIT image reconstruction. Results of numerical experiments of EIT solved by the GA approach are presented and compared to that obtained by the modified Newton-Raphson method. The GA approach is relatively expensive in terms of computing time and resources, and at present this limits the applicability of GA to the field of static imaging. However, the continuous and rapid growth of computing resources makes the development of real-time dynamic imaging applications based on GA´s conceivable in the near future.

• Journal of Hydrospace Technology
• /
• v.2 no.2
• /
• pp.24-35
• /
• 1996

This paper describes parameter identification techniques formulated for the estimation of maneuvering coefficients of a submerged body. The first part of this paper is concerned with the identifiability of the system parameters. The relationship between a stochastic linear time-invariant system and the equivalent dynamic system is investigated. The second is concerned with the development of the numerically stable identification technique. Two identification techniques are tested; one is the ma7mum likelihood (ML) methods using the Holder & Mead simplex search method and using the modified Newton-Raphson method, and the other is the modified extended Kalman filter (MEKF) method with a square-root algorithm, which can improve the numerical accuracy of the extended Kalman filter. As a results, it is said that the equations of motion for a submerged body have higher probability to generate simultaneous drift phenomenon compared to general state equations and only the ML method using the Holder & Mead simplex search method and the MEKF method with a square-root algorithm gives acceptable results.