• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.267-270
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• 2001

A lot of efforts have been made to analyze the performance of the vehicle equipped with automatic transmission through simulation. It might be necessary to understand the different types of transmissions, i.e., different power flows, for different models. If there is a module that can be applied to different types of automatic transmission, it could be helpful to transmission-related engineers. This study has started up from this idea. The common bond graph has been obtained from several types of the automatic transmission. The overall generalized equations and kinematic constraint equations have been derived using virtual power sources on common bond graph. They are used to derive state equations and constraints. These equations have been applied as an application to the vehicle equipped with two simple planetary gear set type of Ravigneaux gear type automatic transmission. The state equation, kinematic constraints, and dynamic constraints have been derived in every gear and shift operation using overall generalized equations and kinematic constraint equations. Simulations for constraint speed running, standing-start running, rolling-start running, and LA-4 mode have been conducted to analyze the performance of the vehicle powertrain using GVPS(Generalized Vehicle Powertrain Simulation) program wit pull down menus.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.10
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• pp.480-488
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• 2001

This paper presents a technique that can obtain an optimal solution for the Security-Constrained Economic Dispatch (SCED) problems using the Interior Point Method (IPM) while taking into account of the power flow constraints. The SCED equations are formulated by using only the real power flow equations from the optimal power flow. Then an algorithm is presented that can linearize the SCED equations based on the relationships among generation real power outputs, loads, and transmission losses to obtain the optimal solutions by applying the linear programming (LP) technique. The objective function of the proposed linearization algorithm are formulated based on the fuel cost functions of the power plants. The power balance equations utilize the Incremental Transmission Loss Factor (ITLF) corresponding to the incremental generation outputs and the line constraints equations are linearized based on the Generalized Generation Distribution Factor (GGDF). Finally, the application of the Primal Interior Point Method (PIPM) for solving the optimization problem based on the proposed linearized objective function is presented. The results are compared with the Simplex Method and the promising results ard obtained.

• Journal of Korea Water Resources Association
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• v.31 no.5
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• pp.565-574
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• 1998

The friction factor distribution of commercial pipes vary according to the pipe type and size. The present paper developed the friction factor equations of power law by analyzing the data reported by Colebrook(1938). Generally, pipe design requires pump power, discharge or pipe diameter for each condition given. Yoo(1995b) has suggested the basic equations for the explicit design of uniformly rough pipe and Yoo and Kang(1996) have refined those equations for the cases of uniformly rough pipe on a sloping bed with a pumping power. Furthermore Yoo and Kang(1997) have studied the design of commercial pipe for a general case. The approach gives relatively accurate solutions, but the equations obtained are rather complicated. In the present study two types of power law are developed for the friction factor of commercial pipe, and explicit forms of equations are generated by applying the power law friction factor equations for the simple design of commercial pipes.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.8-9
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• 2006

This paper presents a new methodology to calculate an optimal solution of equilibrium to power system differential algebraic equations. It employs a nonlinear interior point method for solving the optimization formulation, which includes dynamic equations representing two-axis synchronous generator models with AVR and speed governing control, algebraic equations, and steady-state nonlinear loads. Equilibrium optimization (EOPT) is useful for diverse purposes in power system analysis and control with consideration of the system frequency constraint.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.22 no.4
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• pp.289-294
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• 2018

In this work, a recently developed semi-analytic technique, so called the residual power series method, is generalized to process higher-dimensional linear and nonlinear partial differential equations. The solutions obtained takes a form of an infinite power series which can, in turn, be expressed in a closed exact form. The results reveal that the proposed generalization is very effective, convenient and simple. This is achieved by handling the (m+1)-dimensional Burgers equation.

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.2
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• pp.21-42
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• 1989

Recently, multi-branced driving systems are often used for power station systems or for marine propulsion systems to save the initial cost, the man power and to improve the energy efficiency. As the multi-branched power system has a very complicated vibrating system, its analyzing method is quite different from the ordinary method for the single straight system. In this study, the multi-branched power system is reduced to derive equations of free vibration and some analytical methods are studied to solve these equations and computer programs are developed to calcuate their numerical solutions. And also, equations of forced-damped vibration of the multi-branched power system which involves diesel engines are derived and their solving methods are studied. Some computer programs are developed to get responses of the forced vibration with damping and their results are synthesized to get resultant responses. Finally, exciting forces of diesel engine and damping forces of power driving systems are appreciated to help field engineers by suggesting reasonable method of estimating their values.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.480-483
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• 1997

A fossil power plant can be modeled by a lot of algebraic equations and differential equations. When we simulate a large, complicated fossil power plant by a computer such as workstation or PC, it takes much time until overall equations are completely calculated. Therefore, new processing systems which have high computing speed is ultimately needed to develope real-time simulators. Vital points of real-time simulators are accuracy, computing speed, and deadline observing. In this paper, we present a enhanced strategy in which we can provide powerful computing power by parallel processing of DSP processors with communication links. We designed general purpose DSP modules, and a VME interface module. Because the DSP module is designed for general purpose, we can easily expand the parallel system by just connecting new DSP modules to the system. Additionally we propose methods about downloading programs, initial data to each DSP module via VME bus, DPRAM and processing sequences about computing and updating values between DSP modules and CPU30 board when the simulator is working.

• Journal of electromagnetic engineering and science
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• v.4 no.4
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• pp.150-155
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• 2004

Universal design equations are presented for the H-plane T-junction power divider with a circular conducting post in a rectangular waveguide. For a given operating frequency and power split ratio, the post offset from the T-junction center line, the distance between the post and the waveguide wall, and the post diameter can be adjusted to obtain a minimum reflection at the input waveguide. Optimum values of the post offset are given in terms of the normalized frequency and the power split ratio. Corresponding values of the post diameter and the distance of the post from the waveguide wall are given in terms of the normalized frequency and the post offset.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.433-438
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• 1997

It Is necessary to calculate radwaste effluent due to change in the fuel defect rate to see the overall change in radwaste effluent md, at present, for this type of calculation DAMSAM code is being used. However, often, one can not access easily to this code with many reason and so we have chosen this case, in this paper, to show a very simplified but quite accurated calculation method without the solving equations. The physical meanning of the parameters in the equations used in DAMSAM have been reviewed to simplify the equations and the result calculated with this method have been compared with that of DAMSAM.

• Interaction and multiscale mechanics
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• v.1 no.1
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• pp.53-81
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• 2008

The theory of microlocal analysis of hyperbolic partial differential equations shows that the energy density associated to their high-frequency solutions satisfies transport equations, or radiative transfer equations for randomly heterogeneous materials with correlation lengths comparable to the (small) wavelength. The main limitation to the existing developments is the consideration of boundary or interface conditions for the energy and power flow densities. This paper deals with the high-frequency transport regime in coupled heterogeneous structures. An analytical model for the derivation of high-frequency power flow reflection/transmission coefficients at a beam or a plate junction is proposed. These results may be used in subsequent computations to solve numerically the transport equations for coupled systems, including interface conditions. Applications of this research concern the prediction of the transient response of slender structures impacted by acoustic or mechanical shocks.