• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.8 no.2
• /
• pp.49-55
• /
• 2008

To address the convergence issue of power control algorithms, a number of algorithms have been developed hat shape the dynamics of up-link power control for cellular network. Power algorithms based on fixed point iterations can be accelerated by the use of various methods, one of the simplest being the use of Newton iterations, however, this method has the disadvantage which not only needs derivatives of the cost function but also may be weak to noisy environment. we showed performance of the power control schemes to solve the fixed point problem under static or stationary channel. They proved goof performance to solve the fixed point problem due to their predictor based optimal control and quadratic convergence rate. Here, we apply the proposed power control schemes to the problem of the dynamic channel or to dynamic time varying link gains. The rigorous simulation results demonstrated the validity of our approach.

• Proceedings of the Korean Institute of Interior Design Conference
• /
• 1999.04a
• /
• pp.71-74
• /
• 1999

Mechanical world view was built by Newton and Decarte approximately 400 years ago. Modern Society has reached at the time for fundamental adjustment and in effect, the paradigm shift is now under way. The new paradigm is the holistic world view that considers the world as the integrated entirety rather than the unity of separated parts. The pluralistic phase which can be considered as general characteristics observed in the art, society and culture in the end of the 20th century is seen as the reflection of this new world view. the complementary relationship between traditionism and modernity and oriental intuitive, holistic approach and western rational analytical approach can be explained when the complementary relationship is recognized with holistic and integrated view. The holistic paradigm and integrated-artistic view are the new aesthetic value which can suggest an alternative for public art of environmental design.

• 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.

• Tribology and Lubricants
• /
• v.17 no.6
• /
• pp.435-440
• /
• 2001

A numerical analysis between the piston and cylinder in hydraulic piston pumps under reciprocating motion is presented. A finite difference method and the Newton-Raphson method are used simultaneously to solve the Reynolds equation in the clearance and the equation of motion for the piston. The tapered piston showed stable behaviors regardless of their initial eccentric positions in the clearance, and the reciprocating speed affect highly on the piston end trajectories. Therefore, the numerical methods and results of present study can be used in the lubrication study of other piston-cylinder type fluid machineries.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.7 s.172
• /
• pp.102-111
• /
• 2005

In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.3C no.5
• /
• pp.199-206
• /
• 2003

Numerical solutions to complex characteristic equations are quite often required to solve electromagnetic wave problems. In general, two traditional complex root search algorithms, the Newton-Raphson method and the Muller method, are used to produce such solutions. However, when utilizing these two methods, the choice of the initial iteration value is very sensitive, otherwise, the iteration can fail to converge into a solution. Thus, as an alternative approach, where the selection of the initial iteration value is more relaxed and the computation speed is high, Davidenko's method is used to determine accurate complex propagation constants for leaky circular symmetric modes in circular dielectric rod waveguides. Based on a precise determination of the complex propagation constants, the leaky mode characteristics of several lower-order circular symmetric modes are then numerically analyzed. In addition, no modification of the characteristic equation is required for the application of Davidenko's method.

• Proceedings of the KIEE Conference
• /
• 1997.07c
• /
• pp.790-793
• /
• 1997

The most of conventional power flow(PF) calculations which adopt the well-known numerical methods such as Newton-Raphson method often diverge in certain critical cases like near the voltage collapse point. Some Approaches have been reported for the application of Genetic Algorithm(GA) to PF problem to overcome the disadvantages mentioned above. This paper presents a new application technique of GA for PF problem, in which some improvements and modifications are made ; modification of fitness function, improvements on crossover method, mutation law and convergence criterion, introduction of reactive power check routine. Some case studies with IEEE 5, 6, 14 bus systems are performed to show the performance of proposed algorithm.

• Structural Engineering and Mechanics
• /
• v.43 no.5
• /
• pp.583-605
• /
• 2012

This paper presents a spatial catenary cable element for the nonlinear analysis of cable-supported structures. An incremental-iterative solution based on the Newton-Raphson method is adopted for solving the equilibrium equation. As a result, the element stiffness matrix and nodal forces are determined, wherein the effect of self-weight and pretension are taken into account. In the case of the initial cable tension is given, an algorithm for form-finding of cable-supported structures is proposed to determine precisely the unstressed length of the cables. Several classical numerical examples are solved and compared with the other available numerical methods or experiment tests showing the accuracy and efficiency of the present elements.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.5
• /
• pp.389-396
• /
• 2003

Systematic methods to calculate thermodynamic properties of carbon dioxide, HFC-l34a and HCFC-22 are presented. First, application of a basic method to identify the saturation state with given temperature or pressure is attempted and the feasibility of auxiliary equations is tested. Next, detailed procedures are suggested to tell a phase when temperature/pressure and another property are specified. Finally Newton-Raphson method is applied to calculate unknown thermodynamic properties fixing the state with the two independent properties specified. The procedures described here are utilized to develop a computer program, which is used to find the relation between temperature and pressure with maximum isobaric heat capacity for super-critical carbon dioxide.

• Journal of Ocean Engineering and Technology
• /
• v.2 no.2
• /
• pp.71-77
• /
• 1988

For the collapse of structures due to the variable repeated load, two types of collapse mechanisms, i.e., incremental collapse and alternating plasticity, exist. Under the similar variable repeated loading conditions there exists shakedown state in the structures. In shakedown state, the number of plastic hinges are not increased and all further loading will be resulted in the elastic moment changes. Namely, under the shakedown state, structures do not collapse. In this investigation, shakedown analysis are performed by composing new computer programs. Basic theories employed to compose the programs are as follows. 1. Newton-Raphson methods are added to the existing matrix method for the plastic analysis. 2. An effort to construct the stiffness of axial and bending springs attached at both ends of the member has been made. By using the programs developed, it is possible to anticipate the collapse mechanisms (Incremental collapse, alternating plasticity). Lastly for the verification of performance of the program, demonstration examples have been solved and the results are compared with other sources.