• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.85-89
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• 2001

Hamiltonian modeling approach has been extensively adopted for rigid body dynamics whereas its usage for deforming flexible continuum dynamics has been limited. A set of Hamilton＇s equations for flexible body motion with finite deformation has been derived and applied for a nonlinear impact problem.

• Proceedings of the Korean System Dynamics Society
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• 2006.04a
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• pp.1-18
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• 2006

• Korean System Dynamics Review
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• v.10 no.3
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• pp.105-124
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• 2009

The situation of the global food markets has been being rapidly restructured and entering on a new phase by new dynamic and driving forces. The factors such as economic growth and income increase, high energy price, globalization, urbanization, and global climate change are transforming patterns of food consumption, production, and markets. The prices and markets of world food and energy are getting increasingly linked each other. Food and fuel are the global dilemma issues associated with the risk of diverting farmland or of consuming cereals for biofuel production in detriment of the cereals supply to the global food markets. An estimated 100 million tons of grain per year are being redirected from food to fuel. Therefore, the objectives of this study are as follows: Firstly, the study examines situations of the world food and energy resources, analyzes the trends of prices of the crude oil and biofuel, and formulates the food-energy links mechanism. Secondly, the study builds a simulation model, based on system dynamics approach, for not only analyzing the global cereals market and energy market but also forecasting the global production, consumption, and stock of those markets by 2030 in the future. The model of this study consists of four sectors, i.e., world population dynamics sector, global food market dynamics sector, global energy market dynamics sector, scenario sector of world economic growth and oil price.

• Korean System Dynamics Review
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• v.13 no.1
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• pp.133-157
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• 2012

This paper aims to propose the strategy making in social enterprise for ensuring organizational sustainability and governance of social enterprise from systems thinking's perspective. Based on previous reviews on organizational sustainability and theories of governance currently advocated in the social enterprise literature, we use 'Holon Dynamics' approach, which is a synthesis of System Dynamics and Soft Systems Methodology (SSM), offers the problem-solving method for dealing with social contexts and "ill-defined" situations. To do so, a researcher carried out the interpretive action research using 'Holon Dynamics' approach from September, 2009 to August, 2010. The outcomes of research are summarized as follows. Firstly, systems methodologies are useful to offer a strategic choice that makes to achieve an organizational sustainability in the case of Korean social enterprise; 'the Rediscovery of Korea'. Secondly, systems thinking offers an alternative concept of system, which is known as an 'appreciative system' that is evolved from the mental constructs amongst participants in given situations. Lastly, the paper delineates the usefulness of systems thinking and the process of inquiry, which deal with social contexts (including cultural and political factors), are contributed to making the necessary conditions for organizational legitimacy and the appropriate strategic choice for social enterprise within combined functioning of the two roles of social and commercial activities from systemic perspectives.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.409-414
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• 2007

Nowadays, with the advancement of computational mechanics, and vehicle dynamics simulation linked up with virtual testing laboratory(VTL) and virtual proving ground(VPG) technologies has become a useful method for analyzing numerous driving performances and diverse noise/vibration characteristics. In this paper, the analytical vehicle model based on multi-body dynamics theory was developed to investigate the vibration characteristics according to various road conditions. For the purpose, the whole vehicle parameters, each vehicle's part parameter, and part connecting elements such as spring, damper, and bush were measured by an experiment. Also, the vehicle dynamics model, which includes the front suspension, rear suspension, steering, front wheel, rear wheel, and body subsystems has been constructed for computer simulation. With the developed vehicle dynamics model, three forces and three moments measured at each wheel center were applied to evaluate and analyze dynamics and vibration characteristics for miscellaneous road conditions.

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.15-16
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• 2010

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.118-119
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• 2010

• Journal of the Korea Computer Graphics Society
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• v.25 no.3
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• pp.133-142
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• 2019

In physics-based character animation, trajectory optimization has been widely adopted for automatic motion synthesis, through the prediction of an optimal sequence of future states of the character based on its system dynamics model. In general, the system dynamics model is neither in a closed form nor differentiable when it handles the contact dynamics between a character and the environment with rigid body collisions. Employing smoothed contact dynamics, researchers have suggested efficient trajectory optimization techniques based on numerical differentiation of the resulting system dynamics. However, the numerical derivative of the system dynamics model could be inaccurate unlike its analytical counterpart, which may affect the stability of trajectory optimization. In this paper, we propose a novel method to derive the closed-form derivative for the system dynamics by properly approximating the contact model. Based on the resulting derivatives of the system dynamics model, we also present a model predictive control (MPC)-based motion synthesis framework to robustly control the motion of a biped character according to on-line user input without any example motion data.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1553-1558
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• 2003

The authors investigate influences of manipulator dynamics on and roles of kinesthetic sensation and visual sensation in a Human-Machine Cooperative System (HMCS). At first, the general structure and essential transfer functions of HMCSs are described based on the previous work. Then, after showing theoretical treatment of manipulator dynamics, this paper analyzes the influences on HMCSs in two cases: one is the control design focusing on tool dynamics and reaction force transfer function, and the other is that specifies maneuver transfer function and transfer function for object dynamics variation. In addition to conventional experiments only employing kinesthetic sensation, other experiments with both kinesthetic and visual sensations are performed to examine difference in the roles of these sensations and the validity of the design without the visual sensation.

• Proceedings of the Korean System Dynamics Society
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• 2003.08a
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• pp.1-24
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• 2003

The purpose of this paper was developing a development density control model for urban growth management, using system dynamics modeling. The density control model was developed to see how urban growth, transition, and decay occur depending on the interaction among population, houses, industry structure, land and urban infrastructure such as road, water supply, and sewage treatment facilities. Suggesting adequate level of development density control using the model was another purpose of this paper. The model was applied to An'yang city to estimate the maximum number of population, industry structures, houses, and cars that can be adequately sustained with the current An'yang city's infrastructur capacity. The computer simulation results shows that the city is overpopulated by some 90,000 people. To reduce the population to the adequate level that the current urban infrastructure can sustain, the current city regulation on floor area ratio are needed to be strengthened at least 20 to 35%.