• 한국시스템다이내믹스연구
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• 제14권1호
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• pp.89-104
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• 2013

This study aims to explore the potentials of System Dynamics as a tool to understand the community welfare practice by paying attention to the strengths of System Dynamics to complement the weaknesses of the theories and studies of the community welfare practice. The contents of this study are as follows. First, it draws the limitations of its theories and studies by reviewing the literatures related. Second, it outlines the characteristics of the community welfare practice process as well as the strengths of System Dynamics as a tool to understand the community welfare practice. Third, it presents a causal loop model of System Dynamics applied to the community welfare practice process. Lastly, it concludes with the suggestions and implications of the key research findings. This study is expected to be a basic study to highlight the potentials of System Dynamics as a tool to understand the community welfare practice.

• 한국시스템다이내믹스연구
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• 제8권1호
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• pp.173-186
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• 2007

This research consists of (1) building (or molding) the Dynamics Simulation Model on Return Policy mainly used in publications, phonographs, and computer industry; which are seen used in supply chain contract known as effective control mechanism under the varied supply chain situations, and (2) analyzing the effects that return rates and seller's contract parameters have in the outcome of the model and (3) observing how the effectiveness of Return Policy changes under such circumstances where the buyer's sales ability and the seller's risk inclination are taken into account. Thus, the main purpose of this research lies in analyzing what exactly are the effects (and or outcome) that sales ability and risk inclination have in Return Policy, and additionally by conducting comprehensive research on Supply Chain Policy Dynamics Simulation Model, we will try to prove that not only the Systems Dynamics approach is highly contributive in supply chain management but also that it will serve as a foothold in future research. As a result of the research, supply chain achievement level turned out to be high when Return Policy is enforced, and the achievement level was even higher when seller's sales ability was taken into consideration along with the Return Policy. On the other hand, the achievement level decreased when the seller had risk aversive tendencies.

• 한국ITS학회 논문지
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• 제8권1호
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• pp.1-8
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• 2009

본 연구는 기존의 버스 운영계획모형을 시스템 다이나믹스(System Dynamics : SD) 관점에서 검토하는 것을 주된 목적으로 하고 있다. 결정변수들 간의 선형적 관계에 기초한 교��비용모델에 SD관점을 적용하여 순환적 관계로의 재구성을 시도하였으며, 그 결과물로 최적배차간격모형의 인과지도(Causal Loop Diagram)을 제시하였다. 또한 계량적 시뮬레이션이 가능한 저유량 인과지도(Stock & Flow Diagram)을 작성하여 시뮬레이션 결과의 의미를 논의하였다. 연구결과, 시뮬레이션에 적용한 수식이 기존의 교통비용모형에 토대를 두고 있기 때문에 시뮬레이션 결과가 기존의 연구와 큰 차이를 보이지 않았다.

• 한국시스템다이내믹스연구
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• 제1권1호
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• pp.133-157
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• 2000

This paper deals with the social system from the point of system thinking consisting the fundamental construct of system dynamics. The Bertalanffy's general system theory, having been criticized because of its ambiguity, and the complex science theory, emerging system theory, are integrated by using the system thinking which is characterized with three concepts, 'feedback thinking', 'dynamic thinking', 'operational thinking'. In the integration, system thinking suggests the dynamic pattern of the social system have not only an equilibrium status but also complex status. The science of complexity gives an implication to system dynamics the important of the uncertainty and complexity if we interpret the social system as an open system. To show more concrete description, I simulate the cooperation model based on the iterated prisoner dilemma. The simulation results show the diverse patterns of cooperation and betrayal. Especially the sensitivity of initial payoff will cause the chaotic strategic landscapes as the game gose on. These results mean that we should not give the hasty prescription to control social system artificially. Because social system retains the self-organizing force in itself.

• 한국시스템다이내믹스연구
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• 제3권2호
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• pp.5-27
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• 2002

This paper evaluate and compare effectiveness of urban growth management measures in Korea using system dynamics model. Simple urban dynamics model was used to compare urban growth management measures. Since the late 1960s, Korean government has been implementing various urban growth management measures without much success. In the 1960s, factories, universities, and public agencies were strongly encouraged to move out to local areas. During the 1970s, regulations on greenbelt area was adopted to prevent urban sprawl. Besides, regulations to prevent location of population inducing facilities, and promoting dislocation of those facilities were implemented simultaneously. During the 1990, regulations on total number of factories in the metropolitan area, development fees were adopted. These various method of urban management were compared. Simulation results shows that promoting decentralization of population, preventing population immigration, expanding greenbelt area are effectiveness ones compared to controlling total number of population inducing facilities, and preventing construction of new industries. Some implications of the findings were discussed.

• 한국시스템다이내믹스연구
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• 제3권1호
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• pp.43-60
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• 2002

This paper describes the forecast of wholesale price in competitive Korean electricity market using the system dynamics approach. The system dynamics concepts have been implemented with the Ithink software. This software facilitates the development of stock and flow model with information feedback. Using this model, the future wholesale electricity price can be computed hour by hour, quarterly, and yearly. This model also gives the energy planner the opportunity to create different scenarios for the future of deregulated wholesale markets in Korea. Also It will lead to increased understanding of competitive wholesale market as a complex, dynamic system. Research results show that the plant construction appeared in waves of boom and bust in Korean electricity market like real estate construction. That is, the Korea wholesale market's new power plants and the market price will appear the Boom and Bust cycle. It is very similar behavior as real estate industry. In case of consideration of DSM program, The DSM savings lead to a somewhat different timing of the booms in construction and of price spikes. But the DSM programs do not eliminated the fundamental dynamics of the boom and bust. And the wholesale price is maintained at the lower level compared to the case of without DSM program. However, the unexpected result is found that due to the lower market price, Investor make significantly less investment in new CCs, which leads to the higher wholesale price after 2010. It suggests that the DSM Policy must be implemented with the dynamics of competitive Electricity Market.

• 한국시스템다이내믹스연구
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• 제3권2호
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• pp.49-68
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• 2002

The intent of this study is to develop system dynamics model for assessment of organizational and human factors in nuclear power plant which can contribute to secure the nuclear safety. Previous studies are classified into two major approaches. One is engineering approach such as ergonomics and probability safety assessment(PSA). The other is social science approach such like sociology, organization theory and psychology. Both have contributed to find organization and human factors and to present guideline to lessen human error in NPP. But, since these methodologies assume that relationship among factors is independent they don't explain the interactions among factors or variables in NPP. To overcome these limits, we have developed system dynamics model which can show cause and effect among factors and quantify organizational and human factors. The model we developed is composed of 16 functions of job process in nuclear power, and shows interactions among various factors which affects employees' productivity and job quality. Handling variables such like degree of leadership, adjustment of number of employee, and workload in each department, users can simulate various situations in nuclear power plant in the organization side. Through simulation, user can get insight to improve safety in plants and to find managerial tools in the organization and human side. Analyzing pattern of variables, users can get knowledge of their organization structure, and understand stands of other departments or employees. Ultimately they can build learning organization to secure optimal safety in nuclear power plant.

• 한국시스템다이내믹스연구
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• 제15권3호
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• pp.5-36
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• 2014

The purpose of this paper is to develop a System Dynamics model for estimating the volume of forest resources in the future and simulating the volume of function of public benefit linked to forest resources in dynamic manner. Also it is to analyze the impact when the volume of forest land conversion is controlled by policy using the SD model. The analysis was done at nation-wide for the simulation period 2000 to 2040. Estimated forest area was 6.2 million ha and estimated growing stock was $4.7\;billion\;m^3$ in 2040 from the future forecast without policies. Changing of forest resources, 13.9 billion tons of forest-ground-water storage was estimated, $1.8\;million\;m^3$ of erosion control of forest was estimated and 377 million tons of $CO_2$ absorption was estimated. As a result of simulation with two alternatives, forest area was less reduced and growing stock was bigger than do nothing policy. Also, function of public benefit reflected by changes of forest resources was enhanced. This study contributes to estimate the quantitatively measured volume of forest resources and function of public benefit over the 30 years in Korean forest land in scientific way. Using this SD model, decision maker would develop forest land policies more delicately for deserving forest resources and increasing the volume of function of public.

• 상하수도학회지
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• 제21권1호
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• pp.75-82
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• 2007

When one forecasts urban water demand in a long-term, multivariate model can give more benefits than per capita requirement model. However, the former has shortcomings in that statistically high explanatory power cannot be obtained well, and change in customer behavior cannot be considered. If the past water consumption effects the future water demand, dynamic model may describe real water consumption data better than static model, i.e. the existing multivariate model. On these grounds, this study built dynamic model using system dynamics. From a case study in Seoul and Busan city, dynamic model was expected to forecast water demand more descriptively and reliably.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권2호
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• pp.346-363
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• 2015

We have performed integrated dynamics modeling for a supercavitating vehicle. A 6-DOF equation of motion was constructed by defining the forces and moments acting on the supercavitating body surface that contacted water. The wetted area was obtained by calculating the cavity size and axis. Cavity dynamics were determined to obtain the cavity profile for calculating the wetted area. Subsequently, the forces and moments acting on each wetted part-the cavitator, fins, and vehicle body-were obtained by physical modeling. The planing force-the interaction force between the vehicle transom and cavity wall-was calculated using the apparent mass of the immersed vehicle transom. We integrated each model and constructed an equation of motion for the supercavitating system. We performed numerical simulations using the integrated dynamics model to analyze the characteristics of the supercavitating system and validate the modeling completeness. Our research enables the design of high-quality controllers and optimal supercavitating systems.