• Journal of the Korea Society for Simulation
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• v.12 no.1
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• pp.49-58
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• 2003

There have been growing recognition on the needs of coordination of diverse activities across cross-functional business areas necessarily involving group decision-making processes. Although many group decision-making support tools and methods have been introduced to enable the collaborative processes of group decision-making, they often lack features supporting the dynamic complexity issues. This study proposes system dynamics modeling approach based on simulation techniques to deal with the group decision-making tasks having properties of dynamic complexity.

• Korean System Dynamics Review
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• v.3 no.2
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• pp.113-140
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• 2002

The cost-benefit analysis is a technique for assisting with decision about the use of society's scare resources. There exists no detailed assessment like cost-benefit analysis. But recently, many policy analysts criticized the merit of cost-benefit analysis. As it is, it can be said that partial or approximate estimates of benefit and cost may be more dangerous than helpful. The purpose of this study is to overcome the limit of traditional cost-benefit analysis. For this purpose, we use the system dynamics approach for setting up new cost-benefit analysis, which we named that ‘Dynamics Cost-Benefit Analysis'. The usefulness of ‘Dynamics Cost-Benefit Analysis' is as follows; finding structural causal relationship between cost factors and benefit factors, understanding the long-term behavior of systems economic feasibility. In this study, we apply 'Dynamic Cost-Benefit Analysis' to case that is construction investment of funeral house by local government sector.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.109-118
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• 2005

A functional suspension model is proposed as a kinematic describing function of the suspension that represents the relative wheel displacement in polynomial form in terms of the vertical displacement of the wheel center and steering rack displacement. The relative velocity and acceleration of the wheel is represented in terms of first and second derivatives of the kinematic describing function. The system equations of motion for the full vehicle dynamic model are systematically derived by using velocity transformation method of multi-body dynamics. The comparison of field test results and simulation results of the ADAMS/Car demonstrates the validity of the proposed functional suspension modeling method. This model is suitable for real-time vehicle dynamics analysis.

• KIISE Transactions on Computing Practices
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• v.20 no.10
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• pp.534-542
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• 2014

Multiscale modeling is a new simulation approach which can manage different spatial and temporal scales of system. In this study, as part of multiscale modeling research, we propose the way of combining two different simulation methods, molecular dynamics(MD) and stochastic rotation dynamics(SRD). Our conceptual implementations are based on LAMMPS, one of the well-known molecular dynamics programs. Our prototype of multiscale modeling follows the form of the third party implementation of LAMMPS. It added MD to SRD in order to simulate the boundary area of the simulation box. Because it is important to guarantee the seamless simulation, we also designed the overlap zones and communication zones. The preliminary experimental results showed that our proposed scheme is properly worked out and the execution time is also reduced.

• Journal of Power System Engineering
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• v.2 no.2
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• pp.73-80
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• 1998

The identification of drilling joint dynamics which consists of drilling and structural dynamics and the on-line time series detection of malfunction process is substantial not only for the investigation of the static and dynamic characteristics but also for the analytic realization of diagnostic and control systems in drilling. Therefore, We have discussed on the comparative assessment of two recursive time series modeling algorithms that can represent the drilling operation and detect the abnormal geometric behaviors in precision roundshape machining such as turning, drilling and boring in precision diemaking. For this purpose, simulation and experimental work were performed to show the malfunctional behaviors for drilling operation. For this purpose, a new two recursive approach (Recursive Extended Instrument Variable Method : REIVM, Recursive Least Square Method : RLSM) may be adopted for the on-line system identification and monitoring of a malfunction behavior of drilling process, such as chipping, wear, chatter and hole lobe waviness.

• Korean System Dynamics Review
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• v.9 no.2
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• pp.45-75
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• 2008

Roe Deer has been preserved for 25 years by the local government and the residents in Jejudo. However, the damage and harm of crops of the residents by Roe Deer are increasing as well. So, some experts worry about the unstability of ecosystem in Mt. Halla where Roe Deer live. This paper discuss the suitable number of Roe Deer population in Jejudo to protect the ecosystem in Mt. Halla and minimize the damage of residents in Jejudo. With system dynamics modeling and simulation, the population of Roe Deer at present is estimated about 2,300. However, the population of Roe Deer stays 'unstable balance'. So, a little change such as poaching and the increase of wild dogs may make the balance of ecosystem broken. According to the result of policy test simulation, we should keep on watching the poaching and maintain the number of wild dogs at about 100, so that the ecosystem in Jejudo can be stable. To reduce the moving of Roe Deer to low region, moreover, we should protect the Mt. Halla which is Roe Deer's habitat. If we are indifferent about these efforts, the ecosystem of Roe Deer in Mt. Halla will be ruined.

• Korean System Dynamics Review
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• v.16 no.1
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• pp.5-23
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• 2015

The purpose of this study is to analyze the land-use changes in the coastal areas using system dynamics modeling and to provide directions for effective management to maintain coastal dune areas. This research process consists of four steps: First, we built the basic model based on the causal loop diagram which was analyzed the land-use change of Sindu-ri Coastal Dune. Second, a time series land-use change map using Arc Map was established. Third, the validity of the basic model was tested. Finally, three simulations were performed for the cut over area($100,000m^2/y$, $150,000m^2/y$, $200,000m^2/y$) of windbreak for maintaining the coastal dune areas. Simulation of the basic model showed that the area of the coastal dune will be consistently decreased. Based on the simulation, if windbreak were cut down $150,000m^2/y$, windbreak area will be restored to the target area in 2019. This study has the limitation which the simulation is progressed with a limited variable: area. Therefore, the modeling of coastal dune should be reflected various variables in the further study.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.17-20
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• 2004

This research is focusing on industry dynamics of Korean Mobile Telecommunications Industry. Industry data from 1997 to April 2004 are used to analyze industry dynamics through variety use of case study and system dynamics modeling. As results, we found the importance of initial endowment, firm reputation, and handset subsidy strategy. Along with these player-based characteristics, government impacts on dynamics of competition are also investigated.

• Korean System Dynamics Review
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• v.13 no.4
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• pp.57-80
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• 2012

This research studies effect of FDA regulations in pharmaceutical industry on new drug development. System dynamics is implemented to demonstrate dynamic relationship between FDA regulations and R&D costs, firm's profits, sales. This research is focused on clinical trials of new medical entity process 50~60% portion of total development cost. Simulation results say that firm's profit is more sensitive to increasing the regulation than alleviating the regulation and effect of regulation policy make different result depending on the intensity of regulation and policy direction. Our simulation model provides the instrumental means for the policy makers and strategic decision in pharmaceutical industry.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.93-99
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• 2009

In this paper, transient voltage response of Polmer Electrolyte Membrane Fuel Cell (PEMFC) stack is analyzed and voltage dynamic characteristic is modeled for optimal design of power conditioning system (PCS). According that the load is changed, the corresponding operating voltage of fuel cell stack is also varied with a certain deep and rising time due to the chemical and mechanical responses. This transient behavior can affect on the operation with respect of PI gain in controller, duty ratio, capacitor of capacitor and so on. So in this paper the detailed theoretical analysis of transient voltage dynamics is explained and the methodology of dynamic modeling is introduced. In addition, the validity and feasibility of the proposed dynamic model is verified by experimental results under various load conditions.