• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1006-1010
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• 2010

This paper discusses the numerical study on the stability of the high-speed EMU by developing its lumped parameter model including the effect of the creepage. The 6, 10 and 14 degrees-of-freedom (DOF) lumper parameter dynamic models are developed and the critical hunting speeds calculated from each model via Matlab software are analyzed and compared. It is demonstrated that the critical hunting speeds decrease while the degrees-of-freedom increase. In addition, the parametric study is conducted to extract major design parameters to influence on the stability of the high-speed EMU.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.7
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• pp.406-412
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• 2013

A hybrid heat pump is under development with the goal of utilizing 120% of primary energy resources. A plate heat exchanger is added between the compressor and air-cooled condenser of an ordinary heat pump to heat water. For successful operation of the heat pump, it is necessary to develop a control algorithm under various operating conditions. As a virtual test bed for that purpose, a dynamic model has been developed, to simulate its dynamic behavior. It was modeled in transient one-dimensions, with varying phase lengths considered. The model was implemented in Matlab and Simulink. Simulation results were effectively applied to design a control algorithm. They also provided physical insight into how to design and operate the system.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.98-104
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• 2003

Model structure of solenoid valve in the automatic transmission is determined as 5th order system by the signal error test. For determining parameter of the solenoid valve, parameters in time discrete model are searched by the least square method. By bilinear transform, we have found the model of solenoid valve in s domain. Afterward, experimental output data is compared with simulated output data by MATLAB having identified parameter. As the result, experimental data is agreed with simulated data very well.

• Interaction and multiscale mechanics
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• v.6 no.1
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• pp.31-50
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• 2013

A five parameter viscoelastic model is developed to study harmonic waves propagating in the non-homogeneous viscoelastic filaments of varying density. The constitutive relation for five parameter model is first developed and then it is applied for harmonic waves in the specimen. In this study, it is assumed that density, rigidity and viscosity of the specimen i.e., rod are space dependent. The specimen is non-homogeneous, initially unstressed and at rest. The method of non-linear partial differential equation has been used for finding the dispersion equation of harmonic waves in the rods. A simple method is presented for reflections at the free end of the finite non-homogeneous viscoelastic rods. The harmonic wave propagation in viscoelastic rod is also presented numerically with MATLAB.

• Journal of applied mathematics & informatics
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• v.29 no.1_2
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• pp.427-442
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• 2011

Calcium is a vital second messenger for signal transduction in neurons. Calcium plays an important role in almost every part of the human body but in neuronal cytosol, it is of utmost importance. In order to understand the calcium signaling mechanism in a better way a finite element model has been developed to study the flow of calcium in two dimensions with time. This model assumes EBA (Excess Buffering Approximation), incorporating all the important parameters like time, association rate, influx, buffer concentration, diffusion constant etc. Finite element method is used to obtain calcium concentration in two dimensions and numerical integration is used to compute effect of time over 2-D Calcium profile. Comparative study of calcium signaling in two dimensions with time is done with other important physiological parameters. A MATLAB program has been developed for the entire problem and simulated on an x64 machine to compute the numerical results.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.443-446
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• 2002

Brushless DC motor(BLDCM) are suitable to operate in a wide speed range, easy to control and since there are no mechanical brushes and commutators, require low maintenance costs and are free from restrictions of application environment. And since the ratio of instantaneous torque and rated torque is high, BLDCM are appropriate for variable speed operation. This paper proposes the optimal model by using Matlab/simulink based on modelling and characteristic analysis of trapezoidal back EMF type BLDCM and verifies the validity of the proposed model by applying control systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1563-1571
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• 2008

In this paper, dynamics modeling of a PEMFC is performed by electro-chemical equations. The developed PEMFC simulation model is implemented using MATLAB Simulink in order to design an optimal PCS for fuel cell systems. In addition, by use of the developed model as an input source of PCS, the validity of the proposed dynamic characteristic model of the PEMFC is verified by various simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.561-570
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• 2010

This paper presents an advanced dynamic simulation model of a proton exchange membrane fuel cell for the optimal design of a fuel cell power conditioning system (FC-PCS). For the development of fuel cell models, the dynamic characteristics of the fuel cell are considered, including its static characteristics. Then, software fuel cell simulation is realized using Matlab-Simulink. Specifically, the design consideration of PCS (i.e., power semiconductor switch, capacitor, and inductor) is discussed by comparatively analyzing the developed simulator and ideal DC source. In addition, a cosimulation between the fuel cell model and PCS realized using the PSIM software is performed with the help of the SimCoupler module. Detailed analysis and informative simulation results are provided for the optimal design of fuel cell PCS.

• Journal of Power Electronics
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• v.12 no.2
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• pp.305-316
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• 2012

The paper presents an accurate loss model based controller of an induction motor to calculate the optimal air gap flux. The model includes copper losses, iron losses, harmonic losses, friction and windage losses, and stray losses. These losses are represented as a function of the air gap flux. By using the calculated optimal air gap flux compared with rated flux for speed sensorless indirect vector controlled induction motor, an improvement in motor efficiency is achieved. The motor speed performance is improved using a fuzzy logic speed controller instead of a PI controller. The fuzzy logic speed controller was simulated using the fuzzy control interface block of MATLAB/SIMULINK program. The control algorithm is experimentally tested within a PC under RTAI-Linux. The simulation and experimental results show the improvement in motor efficiency and speed performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.425-426
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• 2006

This study proposes a new simulation method of high speed rotor system with the dynamic model using multi body dynamic analysis tool and with a new phase modulating technique as a system control algorithm. A dynamic model of high speed rotor system was built by, ADAMS, commercial multi body dynamic program. The phase modulating technique is a new control algorithm for a rotor system. This algorithm can control system using an adaptive proportional gain and an adaptive phase which are obtained from periodical input signal. To make control system, a ADAMS model and component parameters and phase controller was composed by Matlab Simulink And simulate it.