• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.628-634
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• 1995

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformer which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backash and friction. Therefore a dynamic modeling and stste sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensitivity snalysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensitivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design based on the results on the results of dynamic and state sensitivity.

• Structural Engineering and Mechanics
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• v.2 no.2
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• pp.173-184
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• 1994

The objective of this study was to develop a simple and efficient numerical modeling technique for dynamic crack propagation using the finite element method. The study focused on the analysis of a rapidly propagation crack in an elastic body. As already known, discrete crack tip advance with the stationary node procedure results in spurious oscillation in the calculated energy terms. To reduce the spurious oscillation, a simple and efficient moving node procedure is proposed. The procedure does require neither remeshing the discretization nor distorting the original mesh. Two different central difference schemes are also evaluated and compared for dynamic crack propagation problem.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.5
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• pp.442-448
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• 2000

The conventional control of dynamic systems needs accurate mathematical modeling of control systems. But the modeling of dynamic systems require very complex computation process due to complex state equation and many control parameters. Accordingly this paper proposes a state space identification model of the dynamic system using neural networks. The Gauss-Newton method is used to train the proposed neural network and the effectiveness of proposed method is verified through the computer simulation of the Seesaw system identification problem.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.4
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• pp.202-208
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• 2002

In a dynamic game where the players move in a periodical sequence, each player observes the strategy of the others. So the players who move later in a game get to know the moves of others having made before them. Those who move earlier must take this into account in devising their optimal strategy. In the Poolco model, the bidding game is executed periodically. The player participating in the bidding game accumulates the information of its own and others'strategies, and payoffs through the repeated bidding process. Thereby, the players in this game would be able to map out how get the maximum profit, and get closer to the optimal strategy. This paper presents a mathematical modeling for a player to determine his or her optimal strategy at period T, based on the information acquired from the previous rounds for the periods, T-1, T-2, and so on. The proposed modeling is demonstrated with a dynamic fame theory.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.366-371
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• 1995

it is extremely difficult to perform the dynamic experiments with full-scale specimens. For this reason, small-scale structural models offer an attractive means to peform dynamic loading experiments. The purpose of this reserch is to estabilish the reliance for modeling techniques of small-scale specimens subjected to dynamic cyclic loading. This research focused on the similitude requirements for reinforced concrete frame structures subjected to dynamic cyclic loading. Length scale ratio of specimens were 1:2:4, and six specimens were tested at the frequencies of 0.0025Hz~2.0Hz. It was confirmed that modeling techniques based on the similitude requirements were useful method to evaluate the behavior of full-size R/C structures subjected to earthquake type loading.

• ETRI Journal
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• v.34 no.4
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• pp.633-636
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• 2012

A dynamic analysis of an amorphous silicon (a-Si) thin film transistor liquid crystal display (TFT-LCD) pixel is presented using new a-Si TFT and liquid crystal (LC) capacitance models for a Simulation Program with Integrated Circuit Emphasis (SPICE) simulator. This dynamic analysis will be useful when predicting the performance of LCDs. The a-Si TFT model is developed to accurately estimate a-Si TFT characteristics of a bias-dependent gate to source and gate to drain capacitance. Moreover, the LC capacitance model is developed using a simplified diode circuit model. It is possible to accurately predict TFT-LCD characteristics such as flicker phenomena when implementing the proposed simulation model.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.182-187
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• 2007

The accuracy of the results of the rail vehicle dynamic model is dependent on the realism of the track input to the model. An important part of the track input is the irregularities that exist on actual track. This study presents a modeling method for creating track data with the irregularities for use as the input to VAMPIRE, a rail vehicle dynamic analysis program. The characteristics of the measured track data using the mid chord system has been studied and examined the method to create track data with the measured data to apply in the vehicle dynamic analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2259-2265
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• 2000

A dynamic modeling of a rotating pretwist blade which interacts with the fluid is proposed in this study. The hybrid deformation variable modeling method is employed to derive the equations of motion. The external force and moment induced by the fluid (with fixed configurations of the blade) are obtained by fluid flow analysis and tabulated in a database. This database is efficiently utilized to save the computational effort to calculate the dynamic response of the blade. The numerical results show that the fluid affects the transient response as well as frequency characteristics of the system.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1287-1296
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• 2014

This paper is about control of Automated Guided Vehicle for path following using fuzzy logic controller. The Automated Guided Vehicle is a tricycle wheeled mobile robot with three wheels, two fixed passive wheels and one steering driving wheel. First, kinematic and dynamic modeling for Automated Guided Vehicle is presented. Second, a controller that integrates two control loops, kinematic control loop and dynamic control loop, is designed for Automated Guided Vehicle to follow an unknown path. The kinematic control loop based on Fuzzy logic framework and the dynamic control loop based on two PID controllers are proposed. Simulation and experimental results are presented to show the effectiveness of the proposed controllers.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.3
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• pp.50-55
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• 1998

The GMDH(Group Method of Data Handling) is a useful data analysis technique for identification of nonlinear complex systems. Therefore, in this paper the application method of GMDH algorithm for modeling nonlinear dynamic systems is proposed. The identification of dynamic systems by using GMDH consists of applying a set of input/output data and computing the necessary coefficient set dynamically. Also, in this paper, by reducing sequentially the criterion which can adopt or reject the data, a method to prevent excessive computation that is a disadvantage of GMDH is proposed.