• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.48-60
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• 1996

This paper present a new technique for doing realistic computer animation. The method is based on forward dynamic simulation and nonlinear problem solving (parameter optimization) technique. Objects are modelled physically and simulated faithfully while satisfying kinematic and geometric constraints. This forward dynamic simulation gives us very realistic motions especially for non-voluntary motions. Then we extend simulation technique to do animation using parameter optimization. The basic idea is to add motion control over the entire animation. The motion control is finding optimal solutions while satisfying user's animation goals. We provide two different animation technique; one is for rigid body without joint actuators and the other is for rigid body with linear joint actuators. To achieve motion control, we convert single simulation to single nonliner function evaluation while either setting initial conditions as variables for the function or allocating control variables in terms of time. This method is presented with two animation examples: dice-magic and human stand-up.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.167-174
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• 1997

In this paper, the mathematical model of the hydraulic control valve is formulated, that is, this dynamic modeling which includes the motion equations and continuity equations can analyze the dynamic characteristics of the hydraulic control valve. The control valve for the transmission has the Over Speed Protection to protect a hydraulic travel motor. Therefore, this simulation shows the over speed protection and researches the main design parameters. The results of the computer simulation were assured through the experiment. From the comparison between both results, it is shown that this simulation program is useful and effective.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.17-24
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• 2004

This paper established the dynamic model of a flexible Timoshenko beam with geometrical nonlinearities subject to large overall motions by using the finite element method. The equations of motion are derived by using Hamilton principle based on expressing the kinetic and potential energies of the flexible beam in terms of generalized coordinates. The nonlinear constraint equations are adjoined to the system equations of motion by using Lagrange multipliers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.439-446
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• 2004

In this study, the characteristic of the Near Fault Ground Motion which was not considered at the seismic design in our country and how the Near Fault Ground Motion affects the cable-stayed bridge which have long period is analyzed through the dynamic response analysis. So, the object of this study is following that it makes the data which can be utilized as the seismic safety evaluation in case of the cable-stayed bridge taken the near fault in the future.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.175-180
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• 1993

The nonlinear integro-differential equations of motion of a two-link structurally flexible planar manipulator executing contact tasks are presented. The equations of motion are derived using the extended Hamilton's principle and the Galerkin criterion. Also, Models for the wrist-force sensor and impact that occurs when the manipulator's end point makes contact withthe environment are presented. The dynamic models presented can be used to studythe dynamics of the system and to design controllers.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.309-314
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• 1992

Many dynamic mechanical systems, such as parts-feeders, walking machines, and percussive power tools, are described by equations of motion which are discontinuous. The discontinuities result from kinematic constraint changes which are difficult to foresee, especially in presence of impact. A simulation algorithm for these types of systems must be able to algorithmically predict and detect the kinematic constraint changes without any prior knowledge of the system's motion. This paper presents a rule-based approach to the prediction and detection of kinematic constraint changes between bodies with arc and line boundaries. The developed algorithm's ability to accurately and automatically detect the unpredicted changes of kinematic constraints is demonstrated with a numerical example.

• Journal of the Korean Society for Railway
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• v.6 no.4
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• pp.215-220
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• 2003

In this paper the dynamic characteristics of a Swing Motion Bogie, such as a critical speed and a carbody vibration, are investigated in reply to the request of the Meridian Rail Corporation in the United States. Also described are experimental results of the maximum speed, the derailment coefficient, the lateral force, the vertical force, the vibration acceleration and steady state lateral acceleration measured from main line tests.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.53-60
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• 1993

Nonlinear equation of motion due to material nonlinearity of structure is transformed to linear equation of motion by treating the nonlinear elastic force term as an applied force. The solution in a time step is carried out by iterative linear dynamic analysis. The present simple algorithm is varidated by several examples .The results show that this algorithm is and efficient.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.216-222
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• 1998

Effects of translational and rotational motions of the foundation on the dynamic behaviors of a bridge under seismic excitations are examined by utilizing a simplified 3 degree-of-freedom of system. To consider the nonlinear characteristics of the RC pier, a hysteresis model is adapted, which can simulate the inelastic motion of the pier with the stiffness degradation. From results, the portion of the total displacement due to rotational motion of the foundation becomes larger as applied seismic excitation increases.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.185-192
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• 2002

In this study, we choose the sinusoidal shaped arch with pin-ends subjected to sinusoidal distributed excitation to investigate the fundamental mechanism of the dynamic instability. We derive the nonlinear equations of motion to investigate the instability phenomenon of arch structures and Identify the buckling characteristics of sinusoidal shaped arch structures through the nonlinear eigenvalue analysis with discreted equations of motion by Galerkin's method. We examine that phenomenons which direct snapping and indirect snapping with backbone curves to understand occurrence paths of the dynamic buckling.