• Proceedings of the Korean System Dynamics Society
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• 2002.08a
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• pp.51-66
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• 2002

대부분의 기업들이 시장에서의 경쟁우위를 확보하기 위하여 끊임없이 시장을 분석하고 이에 기초한 시장전략을 수립하고 있다. 그러나 기업의 전략적 의사결정은 종종 잘못된 시장분석으로 인하여 전혀 예상하지 못한 결과를 가져오는 경우가 있다. 이는 전체적인 시각에서 시장의 구조적 특성을 분석하기보다는 현상을 조사하는 수준에 머물거나 현재의 상황만을 고려할 뿐 시간의 흐름에 따른 동태적 변화와 지연된 피드백의 효과를 반영하지 못한 채 단기적 관점에서 시장 전략을 수립하는데 그 원인이 있다고 볼 수 있다. 이에 따라 본 논문은 자치단체 서버 시장을 대상으로 모 기업이 시장 전략을 수립하는 과정을 사례로 시스템 사고와 시뮬레이션 모델이 이러한 문제를 해결하는데 얼마나 효과적인지 설명하고자 한다.

• Korean System Dynamics Review
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• v.8 no.2
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• pp.115-140
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• 2007

Changes in material use, energy use and emissions profiles of steel industry are the result of complex interrelationships among a multitude of technological and economic drivers. To better understand and guide such changes requires that attention is paid to the time-varying consequences that technology and economic influences have on an industry's choice of inputs and its associated outputs. We briefly review the range of policy issues in our paper and assess the impact that climate-change policies may have on energy use and carbon emissions in Korea steel industry. We then present the models of Korea steel industry's energy and product flow regarding environmental regulations by using system dynamics simulation methodology(SD). Time series data and engineering information are combined to endogenously specify changes in technologies, fuel mix, and production processes within dynamic simulation model. Through a various scenario, ramifications that the convention of climate change would to steel industry is analyzed, and based on the study results, strategies against environment changes is contemplated in various perspectives to contribute to minimize the risks concerning the uncertain future and to be conducive to Korea steel industry's sustainable development.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1053-1059
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• 2009

Construction system modeling can enhance work performance by following the behaviors of a system. System behaviors may originate from physical aspects of a system, namely operation level variables, or from non-physical aspects of a system known as context level variables. However, construction system modelers usually focus on only one type of system variable (i.e., operation level or context level) which can lead to less accurate results. Hybrid modeling with System Dynamics (SD) and Discrete Event Simulation (DES) is one of the approaches that has been utilized to address this issue. In this research, an SD-DES hybrid model of a steel fabrication shop is developed, and the benefits of capturing context level variables together with operation level variables in the model are discussed.

• Korean System Dynamics Review
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• v.12 no.2
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• pp.153-176
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• 2011

This paper is a summary of how we constructed a national R&D investment model. Although a national R&D investment is an important decision making for the government as well as industries, currently there were little efforts on making a model reflecting governmental decision making on the individual size of national R&D. We constructed a simple national R&D model through discussion with 3 researchers who have rich experience of governmental investment of national R&D. In this paper, we tried to show how our simple R&D model can reflect the perception on the R&D efficiency that changes as the industry reach to its saturation level.

• Korean System Dynamics Review
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• v.5 no.1
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• pp.35-47
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• 2004

Analyzers adopt a variety of techniques in analyzing public policy. Based on the results of exploration, they explain problems and suggest prescriptions such as policy alternatives. By doing so, however, they have different degree of confidence in their own results according to what techniques they adopt. This study explores whether system dynamics apporach gives analyzers more confidence on their own simulation results than other approaches do. This study designed an experiment. Three research teams are organized. Each of them applies different analytic techniques on the same policy issue, i.e., introduction of transportation tax. It flnds that researchers using S,D. simulation technique are most confident on what they predict, while researchers adopting survey techniques show moderate degree of confidence on their results. Researchers using regression are least confident.

• Korean System Dynamics Review
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• v.11 no.3
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• pp.87-104
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• 2010

This research aims at designing policy alternatives which would facilitate the supply of the national rental housing units, especially targeted for the low-income households who need special types of social support for their residences. In order to illuminate structural characteristics of the national rental housing policies, it heavily depends on collection of secondary survey data, in addition to existing documents. From the institutional dimension, it focuses on major issues related to the residential development, which is pivotal in supplying the required national rental housing units. Furthermore, applying causal loop diagramming techniques derived from the System Dynamics (SD), it tries to divulge dynamic relationships between key stakeholders including the government, developers and tenants. Finally, this research stresses the point that the government should fulfill its basic duty as a financial supporter and the developer should not procrastinate in providing diverse options, timely reflecting tenants' needs.

• Proceedings of the Korean System Dynamics Society
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• 2001.10a
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• pp.17-34
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• 2001

최근, 기업 활동은 물론 개인 실생활에 있어서도 지대한 영향을 끼치고 있는 인터넷과 이동통신은 정보통신산업의 양대 축을 이루고 있다. 특히 이 두 주역의 결합으로 등장한 것이 무선 인터넷이다. 아직은 초기 단계라 서비스에 여러 가지 제약이 있으나, 관련 기술이 급속히 발전하고 있고 그 동안의 인터넷과 이동통신의 급속한 발전 패턴을 고려해볼 때 향후 무선 인터넷의 성장 잠재력은 매우 클 것으로 전망된다. 이러한 추세에 따라 많은 연구기관들이 앞다투어 무선인터넷서비스 시장에 대해 연구하고 있으나 대부분의 경우 현황분석에 머무르는 경우가 많거나 신기술 도입 및 확산모형에 따라 막연한 예측을 제공하는데 그치는 경우가 많아 정책적 핵심요소와 방향을 제시하는 데에는 한계를 지니고 있다. 이에 본 논문은 다양한 요인간의 인과관계와 피드백 메커니즘에 근간을 둔 시스템 다이내믹스 개념을 도입하여 무선인터넷 시장의 동적 구조를 분석함으로써 정책수립 및 시행을 위한 시사점을 제공할 수 있는 분석 틀을 제시하고자 하였다.

• Journal of Navigation and Port Research
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• v.27 no.5
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• pp.493-498
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• 2003

Ship is being operated under a highly dynamic environments and many factors are related with ship's collision and those factors are interacting. So, An analysis on the ship's collision muses is very important to prepare countermeasures which will ensure the safe navigation. And the analysis confirmed that ship's collision is occurred most frequently and the muse is closely related with human factor. The main purpose of this study is to build a model of human factors in ship's collision muse using SD(System Dynamics} approach and to measure a effect which is risk control countermeasures of ship's collision. To achieve this aim, the structure analysis on the muses of ship's collision using FSM are performed, and the structure was changed by quantitative, qualitative factors and their feedback loops in casual map. This model was performed over 20 years(1993-2012) in a standard simulation model and 8 policy simulation models.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.131-140
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• 2013

Econometric forecast models based on past time-series data have been applied to a wide variety of applications due to their advantages in short-term point estimating. These models are particularly used in predicting the impact of governmental research and development (R&D) programs because program managers should assert their feasibility due to R&D program's huge amount of budget. The construction governmental R&D programs, however, separately make an investment by dividing total budget into five sub-business area. It make R&D program managers difficult to understand how R&D programs affect the whole system including economy because they are restricted with regard to many dependent and dynamic variables. In this regard, system dynamics (SD) model provides an analytic solution for complex, nonlinear, and dynamic systems such as the impacts of R&D programs by focusing on interactions among variables and understanding their structures. This research, therefore, developed SD model to capture the different impacts of five construction R&D sub-business by considering different characteristics of sub-business area. To overcome the SD's disadvantages in point estimating, this research also proposed the method for constructing quantitative forecasting model using qualitative data. Understanding the different characteristics of each construction R&D sub-business can support R&D program managers to demonstrate their feasibility of capital investment.

• Korean System Dynamics Review
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• v.14 no.4
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• pp.143-163
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• 2013

This study is firstly aiming at diagnosing the present problems of evaluating the performance, especially in the field of disaster and safety management, of LGA (Local Government Authorities) in Korea. The study also deals with developing alternatives to solve a series of barrier factors revealed during the evaluation process using System Dynamics. This paper therefore presents literature review including the official documents published by the government and the performance evaluation studies of LGA. Moreover the authors analyze the current practice of the CELG (Combined Evaluation of Local Governments) as performance management, address and map a series of barrier factors in the CELG process to elaborate the CLDs (Causal-Loop Diagrams) and find solutions using system thinking with the CLDs. According to the analysis results, the core barrier factors to overcome is lack of proactive indicators/indices in the current practice of the CLEG. The authors therefore recommend to develop more proactive indicators that leads to avoid difficulties in measuring the LGA output, as well as to lessen the burden in competition for rankings and goal of the displaced.