• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.42-52
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• 2009

From the beginning of 2000, Korean housing market has experienced cyclical volatility because of the global economic fluctuation such as steady decline in the interest rate and the house price bubble. In response to these state Korean Government announced policies about housing sales system kinds of Sales Unit Price Restraint and Post-Sales System to stabilize housing market. But such policies has brought unprecedented arguments both for and against, most of whom still seem to stick to self-centered judgement ahead of impact on housing market. In an integrated point of view, applying the system dynamics modeling, the paper aims at proposing basic Korean housing market dynamics models based on basis principles of housing market determined by supply and demand. And then, after research policies about housing sales system, analyze Impact on Korean Housing Market by change of Sales Systems applying policies to basic Korean housing market dynamics models.

• Korean System Dynamics Review
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• v.5 no.2
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• pp.125-147
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• 2004

System dynamics model has been developed and computer simulation has been peformed for the evaluation of R&D policy. One of the main results of the basecase scenario is as follows. After simulation of nuclear R&D resource allocation strategies, we discovered that their net benefit value was maximum at 130% nuclear R&D budget case. And after simulation of human resource management strategies and policy research program strategies, we confirmed that it is beneficial to allocate budgets in the early phase for human resources management program and research program for the policy.

• Korean System Dynamics Review
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• v.9 no.2
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• pp.5-25
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• 2008

This paper analysed the impact of return policy as a coordination mechanism for decentralized supply chain with one capacitated supplier and two competing retailers under random demand distribution. In this study, Shortage gaming also considered to reflect a competing environment of two retailers. System dynamics approach was used to model the baseline two echelon supply chain and return policy on it. Given each of 4 experiment settings being used for 100 simulations with different random seeds, 400 random samples were used in a t-test. The result show that return policy significantly enhance the supply chain profits and fillrates. The analysis suggest that the supply chain performance can be build up by implementing a return policy even though under consideration of a capacitated supplier and competing retailers.

• Korean System Dynamics Review
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• v.11 no.2
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• pp.119-138
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• 2010

This study introduces the system dynamics model that simulate total operational availability when 10 equipments made of 3 major components are serviced under the constrains of the maintenance capacity level and the number of spare parts. This simulation is designed on the base of reliability engineering concept so failures of components happens with the rule of engineering factors like the mean time between failure(MTBF) of component and the next failure time of one component is effected by the conditions of other components. We analysed availability of 10 equipments under 121 constrains and executed multiple regression analysis with the simulation result. The analysis provide the managerial insight in the service fields with operation many equipments.

• Korean System Dynamics Review
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• v.5 no.1
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• pp.5-33
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• 2004

This study explores how agents would make decisions responding to control mechanism in contractual relationship of their firm. Focusing on agent's averse behavior against control, system dynamics model for agent's opportunistic behavior is developed in view of agent theory and control theory. This SD model shows that control mechanism by contracts doesn't always play a positive role on corporate decision-making process and Control, especially in the over-controlled contracts, often makes a paradox accelerating agent's opportunistic behavior unexpectedly. This paradox provides us both theoretical and practical implications for the relationship between control mechanism and autonomous behavior for sustainable corporate management.

• Korean System Dynamics Review
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• v.15 no.4
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• pp.85-100
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• 2014

We propose a composite make or buy decision model considering both the transaction cost theory and the resource based view in the Korean defense industry using System Dynamics. We analyze relationship between core variables(transaction frequency, technological uncertainty, the level of technological dependency, technological level and acquisition ability for market information) and 'Make or Buy decision' focused on technological innovation capability. Based on the result, we propose the implications as follows : First, the defence industry needs more R&D investment. Second, it needs a balance between domestic(Make) and overseas(Buy) to increase the technological capability rapidly.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.286-286
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• 1996

A neural predictive tracking system for the control of structure-unknown dynamic system is presented. The control system comprises a neural network modelling mechanism for the the forward and inverse dynamics of a plant to be controlled, a feedforward controller, feedback controller, and an error prediction mechanism. The feedforward controller, a neural network model of the inverse dynamics, generates feedforward control signal to the plant. The feedback control signal is produced by the error prediction mechanism. The error predictor adopts the neural network models of the forward and inverse dynamics. Simulation results are presented to demonstrate the applicability of the proposed scheme to predictive tracking control problems.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.154-161
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• 1996

A neural predictive tracking system for the control of structure-unknown dynamic system is presented. The control system comprises a neural network modelling mechanism for the the forward and inverse dynamics of a plant to be controlled, a feedforward controller, feedback controller, and an error prediction mechanism. The feedforward controller, a neural network model of the inverse dynamics, generates feedforward control signal to the plant. The feedback control signal is produced by the error prediction mechanism. The error predictor adopts the neural network models of the forward and inverse dynamics. Simulation results are presented to demonstrate the applicability of the proposed scheme to predictive tracking control problems.

• Korean System Dynamics Review
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• v.9 no.1
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• pp.155-170
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• 2008

The purpose of this study was to develop a system dynamics model for management of glucose metabolism disorders that demonstrated dynamic relationships between insulin and plasma glucose levels over the time. The model was developed to 1) represent the physiology of glucose metabolism for an normal adult subject, 2) to draw causal loop diagram that demonstrate feedback systems of glucose regulation in normal condition and pathologic condition of the type 2 diabetes, 3) to develop an interactive computer simulation model for management of glucose metabolism disorders. The simulation results showed the plasma glucose level for normal persons varied from 75 to 140 which was consistent with clinical findings. As an example for patients we selected a case which varied from 110 to 310. Two types of interventions were chosen to review the model; meal control and insulin administration. The simulation results for those cases also matched well with clinical findings. The developed model can be used as an effective educational tool for patients to develop healthy lifestyle choices. The results also provide a blueprint for health providers to maintain normal blood glucose levels in diabetes patients.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.847-849
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• 2001

The OSS2(Ojame-Shavitt-Singer 2)[L. Ojame et al., J. Chem. Phys. 109, 5547 (1998)] model as a dissociable water model is examined in order to study the dynamics of H+ in water. MD simulations for 216 water system, 215 water + H+ ion system, and 215 water + OH- ion system using the OSS2 model at 298.15 K with the use of Ewald summation are carried out. The calculated O-H radial distribution functions for these systems are essentially the same and are in very good agreement with that obtained by Ojame.