• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.421-427
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• 2010

In order to visualize the transfer of sound waves, we performed real-time processing with the fast operating system of GPU, the Graphics Processing Unit. Simulation by using the method of the discrete Huygens' model was also implemented. The sound waves were visualized by varying the real-time processing, the reflecting surfaces within the two-dimensional virtual sound field, and the states of the sound source. Experimental results have shown that reflection and diffraction patterns for the sound waves were identified at the reflecting objects.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.04a
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• pp.149-152
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• 2005

In this paper, a robust $H\infty$ stabilization problem to a uncertain discrete-time fuzzy systems with time-varying delay via static output feedback is investigated. The Takagi -Sugeno (T-S) fuzzy model is employed to represent an uncertain nonlinear systems with time-varying delayed state. Using a single Lyapunov function, the globally asymptotic stability and disturbance attenuation of the closed-loop fuzzy control system are discussed. Sufficient conditions for the existence of robust $H\infty$ controllers are given in terms of linear matrix inequalities.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1411-1413
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• 2000

Distubance of air-gap sensors by rail irregularities are the serious problem deteriorating the performance in the electromagnetic suspension (EMS) systems. Thus, this paper proposes the output feedback controller with discrete kalman filter for the EMS systems. The discrete kalman filter estimate true state value and output feedback controller guarantee stability. The benefit of this scheme are shown by simulation. Therefore air-gap disturbance are rejected successfully.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.571-573
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• 1995

This paper presents a method for optimal dispatch which minimizes transmission losses and improves voltage profile of power systems using genetic algorithm based on the mechanism of natural genetics and natural selection. The constraints are VAR sources(transformer tap, generator voltage magnitude and shunt capacitor/reactor), load bus voltages and generator reactive power. Real variable-based genetic algorithms which can save coding times and maintain the accuracy are applied for optimal dispatch of reactive power. The genes of genetic algorithm consisted of integers for considering discrete VAR sources. A efficient operator for crossover is proposed to consider the effect of close genes. The algorithm proposed can apply to problems for large scale power systems with multi-variables and complex nonlinear functions efficiently. The proposed method is applied to IEEE 30 buses model system to show its effectiveness.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.173-175
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• 2015

We proposed a blind watermarking scheme using singular vectors based on Discrete Wavelet Transform (DWT) and Redundant Discrete Wavelet Transform (RDWT) combined with Singular Value Decomposition (SVD) for copyright protection application. We replaced the 1st left and right singular vectors decomposed from cover image with the corresponding ones from watermark image to overcome the false-positive problem in current watermark systems using SVD. The proposed scheme realizes the watermarking system without a false positive problem, and shows high fidelity and robustness.

• Interaction and multiscale mechanics
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• v.6 no.2
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• pp.107-125
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• 2013

A strain smoothing meshfree formulation with stabilized conforming nodal integration is presented for modeling the consolidation process in saturated porous media. In the present method, nodal strain smoothing is consistently introduced into the meshfree approximation of strain and pore pressure gradient variables associated with the saturated porous media. Meanwhile, in order to achieve a consistent numerical implementation, a smoothing approximation of the meshfree shape function within a nodal representative domain is also proposed in the stiffness construction. The resulting discrete system of equations is all expressed in smoothed nodal measures that are very efficient for numerical evaluation. Subsequently the space-time fully discrete equations are further established by the generalized trapezoidal rule for time integration. The effectiveness of the proposed meshfree consolidation analysis method is systematically illustrated by several benchmark problems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.1
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• pp.1-7
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• 2010

A new flow mode of ER fluid available for controlling the damping force by using DME(Discrete Multi-Electrode) is presented in this study. Various characteristics about the flow of ER fluid through the experiment of ER cluster behavior visualization can be assumed. The pressure in electrode length and voltage division mode is measured. An actuator with a damping effect through DME ER damper will be developed. This damper controls the damping force by using the displacement and velocity of the plant which consists of the various electrode length and voltage modes without a controller in the real system.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.475-480
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• 2008

A pre/post processor program based GUI(Graphic User Interface) by using the MFC and OpenGL library in the Windows OS have been developed for the analysis of the passenger flow. Using this program, users are able to generate and modify the meshes of multi-storied subway station, set all the parameters for the solver, and obtain the results of the simulation such as transient passenger motions and passenger streak lines in 3-dimensional graphic view.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.632-638
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• 1997

The growing number of electronic components used in automobiles has given rise to problems concerning the increasing number, size and weight of the wiring harnesses. As an approach to resolve these problems, multiplexed wiring systems using automotive communication protocol such as Controller Area Network(CAN), Advanced PALMNET and J1850 have been developed by many automobile companies. In order to compare these protocols quantitatively, this paper presents the performance evaluation of CAN and Advanced PALMNET via discrete event simulation. Through numerous simulation experiments, several important quantitative performance factors such as the probability of a transmission failure, average system delay(data latency), and throughput have been evaluated.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.3
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• pp.24-32
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• 1997

This paper is on a discrete controller order reduction with the closed-loop stability and performance guaranteed. to achieve this, after finding the solutionsof two lyapunov inequalities and balancing the full order controller system, we find the reudced order controlers using the balanced truncation (BT) and the balanced singular perturbation approximation (BSPA). When the solutions of the two lyapunov inequalities exist, it is shown that the resulting controllers guarantee the closed-loop stability, and .inf.-norm error bounds are derived for the closed-loop performance region for the BT and in low frequency region for the BSPA. Finally, a numerical example is given to illustrate the validity of the proposed method.