• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1225-1227
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• 2004

The robotic shoe testing system that mechanically simulates human motion was proposed to overcome the problems associated with human subject tests. The objective of this study is to predict new motion trajectory for robot that will produce similar force and moment of particular human motion. In order to solve this problem, it is imperative to understand the dynamics of robot for shoe testing. The methodology using parameter estimation technique was proposed for this problem. Since the dynamics of robot is certainly different from that of human, it is necessary to adapt/modify the robot's trajectory for future analysis, which is currently under investigation.

• Korean System Dynamics Review
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• v.10 no.1
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• pp.33-60
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• 2009

This study explores the limitation in making a causal model through an existing case and proposes an alternative plan to improve a theoretical system of causation modeling. To make a dynamic and actual model, several principles are needed such as reality based analysis of system structures and dynamics, consistent expression of causations, conversion of numerical formulas to causal relations, classification and arrangement of variables by size of concept, etc. However, it is hard to find cases to apply these considerations from existing models in System Dynamics. Therefore, this study verifies errors of derived models from literatures and proposes principles and guides that should be considered to make a sound dynamic model on a causal map. It contributes to making an opportunity for exciting public opinion to improve theory about causal maps, yet it has limitation that the study does not advance forward to the experimental step. For future study, it plans to make up by classifying and leveling causal variables, developing a dynamic BSC model.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.81-84
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• 2012

Cantilevered carbon-nanotube-resonator was investigated via classical molecular dynamics simulations. The resonator system is including the attached nanocluster. A nanocluster with a finite length was modeling by some atomic rings. The mass of the nanocluster was equally distributed on the carbon atoms, composed of the atomic rings. The effective density factor, which could be considered as the single parameter affecting the resonance frequency shift, was significantly influenced by the mass, the position, and the linear density of the attached nanocluster. The linear density of the attached nanocluster was an important parameter to analyze the vibrational behavior of the CNT-resonator, including the attached nanocluster.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.12
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• pp.1181-1188
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• 2004

This paper reviews the main aspects of cardiovascular system dynamics with emphasis on modeling hemodynamic characteristics using a lumped parameter approach. Methodological and physiological aspects of the circulation dynamics are summarized with the help of existing mathematical models: The main characteristics of the hemodynamic elements, such as the heart and arterial and venous systems, are first described. Lumped models of micro-circulation and pulmonary circulation are introduced. We also discuss the feedback control of cardiovascular system. The control pathways that participate in feedback mechanisms (baroreceptors and cardiopulmonary receptors) are described to explain the interaction between hemodynamics and autonomic nerve control in the circulation. Based on a set-point model, the computational aspects of reflex control are explained. In final chapter we present the present research trend in this field and discuss the future studies of cardiovascular system modeling.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.838-847
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• 1994

Although there is an analytical proof of modeling capability of the neural network, the convergency error in nonlinearity modeling is inevitable, since the steepest descent based practical larning algorithms do not guarantee the convergency of modeling error. Therefore, it is difficult to apply the neural network to control system in critical environments under an on-line learning scheme. Although the convergency of modeling error of a neural network is not guatranteed in the practical learning algorithms, the convergency, or boundedness of tracking error of the control system can be achieved if a proper feedback control law is combined with the neural network model to solve the problem of modeling error. In this paper, the neural network is introduced for compensating a system uncertainty to control a nonlinear dynamic system. And for suppressing inevitable modeling error of the neural network, an iterative neural network learning control algorithm is proposed as a virtual on-line realization of the Adaptive Variable Structure Controller. The efficiency of the proposed control scheme is verified from computer simulation on dynamics control of a 2 link robot manipulator.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.576-583
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• 2000

A robust position control using a sliding mode controller is adopted for the stable dynamic walking of the biped. For the biped robot that is modeled with 14 degrees of freedom rigid bodies using the method of the multibody dynamics, the joint angles for simulation are obtained by the velocity transformation matrix using the given Cartesian foot and trunk trajectories. Hertz force model and Hysteresis damping element which is used in explanation of the energy dissipation during contact with ground are used for modeling of the ground reactions during the simulation. By the obtained that forces which contains highly confused noise elements and the system modeling uncertainties of various kinds such as unmodeled dynamics and parameter inaccuracies, the biped system will be unstable. For that problems, we are adopting a nonlinear robust control using a sliding mode controller. Under the assumption that the esimation error on the unknown parameters is bounded by a given function, that controller provides a successful way to preserve stability and achieve good performance, despite the presence of strong modeling imprecisions or uncertainties.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.18-21
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• 1996

Even though there are several deterministic methods for the modeling of linear systems, there is no standard method for the modeling of nonlinear systems. For the modeling of nonlinear systems we have applied the genetic programming method to estimate nonlinear time sereis. We get the time series from the simple known nonlinear dynamics, and fed those to genetic programming. For the tested nonlinear systems, suggested method estimated the nonlinear dynamics correctly.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.245-254
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• 2017

In this paper, deployment dynamics of large-scale flexible solar arrays with deployable mast is investigated. The adopted solar array system is introduced firstly, then kinematic description and kinematic constraint equations are deduced, and finally, dynamics equation of the system is established by the Jourdain velocity variation principle and a new method to deal with topology changes of the deployable mast is introduced. The dynamic behavior of the system is studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the solar arrays and that the introduced method is applicable for topology changes.

• Korean System Dynamics Review
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• v.1 no.1
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• pp.29-56
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• 2000

During the past few years, cyberspace and electronic commerce has been expanding throughout the world rapidly. The purpose of this paper is to find out policy leverages for boosting up cyberspace and electronic commerce using system dynamics simulation modeling approach. The system dynamics simulation model developed in this paper allows analysis of both the effect of factors on dynamic growth pattern of cyberspace as well as the effect of time delay in information processing, money transfer and delivery on model behavior. Finding of this study is that capacity of information infrastructure and size of cyberspace population are key factors of cyberspace growth. Also, reducing time delay in information flow, money flow, and delivery flow is an important policy leverages for growth of electronic commerce.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.968-974
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• 2017

In this paper, modeling of brushless DC motor (BLDC) driving system for platform screen door control applied fuel cell power generation system has been proposed. At first the system configuration and operational principle of the developed fuel cell simulator has been investigated and the design of BLDC motor driving system is studied and the overall performance and dynamics of the proposed system could be effectively examined by simulation. PSIM simulation program is implemented to verify the performance and compatibility of the fuel cell power generation system and BLDC motor control system modeling.