• Journal of the Society of Naval Architects of Korea
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• v.61 no.4
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• pp.247-257
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• 2024

The present study suggests a data-driven multivariate identification method based on principal component analysis and shows an application to ship dynamics modeling in maneuver. A reduced order model of ship dynamics is built by linear combination of three principal components acquired from large angle zigzag maneuver test. For a given kinematic state with three variables, a proper span is found by least square method, therefore accompanying hydrodynamic force and moment is determined. Suggested dynamics model correctly estimates hydrodynamic force and moment, thus it showed good agreement in maneuver simulation with that of conventional ship dynamics model obtained by system identification of captive model tests.

• Proceedings of the Korean System Dynamics Society
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• 2007.11a
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• pp.33-48
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• 2007

Recently, due to the globalization of business, the efficient supply chain management(SCM) is considered as the key initiatives of business activities, and the leading logistics companies are trying to provide the differentiated 3PL services to meet their customers' needs. The domestic 3PL market scale, however, is still small and the logistics companies' competence is not good enough, so that 3PL companies need to concentrate on their logistics strategies and the government's supports and related policies are required. In this point of view, we developed the system dynamics model and forecasted middle or long-term domestic 3PL market. Through the result, we suggest the roles of government and the directions of policies to support the domestic 3PL market effectively.

• Korean System Dynamics Review
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• v.9 no.1
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• pp.107-123
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• 2008

Recently, due to the globalization of business, the efficient supply chain management(SCM) is considered as the key initiatives of business activities, and the leading logistics companies are trying to provide the differentiated 3PL services to meet their customers' needs. The domestic 3PL market scale, however, is still small and the logistics companies' competence is not good enough, so that 3PL companies need to concentrate on their logistics strategies and the government's supports and related policies are required. In this point of view, we developed the system dynamics model and forecasted middle or long-term domestic 3PL market. Through the result, we suggest the roles of government and the directions of policies to support the domestic 3PL market effectively.

• Korean System Dynamics Review
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• v.11 no.1
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• pp.59-83
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• 2010

The Korean Government decided to reduce 30% of carbon emissions as of 2020, tightening regulations to reduce greenhouse gas in the international society. Therefore it will burden Korean logistics industry that overland trucking freight covers 70~80% of all, to lower emissions. As known, rail and coast(feeder) transport systems can be substituted for road transport but there are many problems to solve in Korean multimodal (intermodal) transport system such as time, cost, etc. Because of this, multimodal transport system should be improved systematically. For the reason, it aims to study a conceptual model with Thinking Process of TOC(theory of constraints) and System Dynamics to help improve the existing multimodal transport system for green logistics.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.834-840
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• 2001

A real time multibody vehicle dynamics model has been developed and implemented using a subsystem synthesis method based on recursive formulation. To verify real time simulation capability the developed model has been applied to HMMWV(High Mobility Multipurpose Wheeled Vehicle) with steering system. For the kinematically driven steering system, the coupled front suspension-steering subsystem can be decoupled into two SLA suspension subsystems, which improves the efficiency of simulation. To investigate theoretical efficiency, operational counting method has been also employed to compare the proposed model with the conventional recursive dynamics model. Various simulations such as unsymmetric bump run, step steering(J-turn) and sine steering input test have been carried out to verify the real time feasibility of the proposed model.

• Korean System Dynamics Review
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• v.8 no.2
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• pp.51-82
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• 2007

The purpose of this paper is exploring changes in land use pattern when considering environmental carrying capacity. A sustainable development requires a society to define sustainability constraints, environmental carrying capacity. Environmental carrying capacity can be defined as a level of human activity a region can sustain at a desired level of quality of environment. This concept of environmental carrying capacity can be applied to land use to explore sustainable land use pattern. Since land use pattern can affect environment in an important way, exploring sustainable land use pattern within the limit of environmental carrying capacity can suggest useful implications for a sustainable regional management and planning. For this purpose, this paper built the environmental carrying capacity land use model and applied it to the Metropolitan Area, Korea. System dynamics modeling methods was used to build the model. The model developed in this paper consisted of 6sectors; population, housing, industry, land, environment, and traffic sector. The model limits its main focus on the NO2 level as an indicator of quality of environment in Metropolitan Area. Box model was translated into system dynamics model and combined to urban dynamics model to estimate NO2 level, the maximum number of population, industry structure, housing and maximum amount of land use for industrial, housing, and green space that can sustain desirable NO2 level. Metropolitan area was divided into 16 areas and the model was applied to each area. Since NO2 is flowing in and out from each area, model was built to allow this transboundering nature of air pollutants. Based on the model estimation, several policy implications for a sustainable land use pattern was discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.669-674
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• 1989

Robot manipulators are highly coupled nonlinear systems and their motions are influenced by uncertain dynamics. In this paper a design methodology which is called model feedback control system or plant model control scheme is presented for the purpose of reducing the influence of the uncertain dynamics. This control system is applied to the trajectly control of the directly drived robot. Theoretically and experimentally performances resulting from use of this control scheme show that the influences of the uncertain dynamics are reduced obviously.

• Korean System Dynamics Review
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• v.9 no.2
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• pp.27-43
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• 2008

This study investigates market barriers in increasing the market share of Alternative Fuel Vehicles (AFVs). In particular, this study first conceptualizes the AFVs market model with the aid of generic system archetypes suggested by Wolstenholme. Among four generic system archetypes suggested by Wolstenholme, the market structure of AFVs can be explained by the 'relative achievement' archetype. Starting from the generic system archetype, this study extends the model boundary step by step to take account of various model assumptions necessary to simulate the model numerically. If there is a significant network effect on vehicle operating costs, it is difficult to achieve the shift to AFVs even in the long term without a policy intervention because the car market is locked into the current structure. There are several possible policy options to break the 'locked-in' structure of the car market, such as subsidies on vehicles, subsidies on fuels, and a niche management policy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.624-627
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• 2002

Experimental study showed that the existing mathematical model doesn't fully describe the lateral motion of a moving web fur different operating conditions. So, a physically interpretable model of lateral motion of a moving web in a typical web guidance system, operated at Konkuk Univ., was developed using the system identification technique. A well-known Least Square Method based on ARX model was used for the system identification. Lateral displacement of the web was measured at the exit of each span by infrared sensors. The model obtained from identifying a linear time-invariant system for a typical operating condition yields an improved prediction capability of the lateral dynamics of the moving web compared to other mathematical models proposed in literature.

• KIEAE Journal
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• v.9 no.5
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• pp.53-61
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• 2009

Green Building Certification System currently going into effect is a static evaluation model. Therefore, as far as the sustainable development of certification system is concerned, further long-term evaluation is required. The main purpose of this study is to offer a model in a way of developing and verifying a dynamic model in Green Building Certification. A dynamic model development has been given System Dynamics based on the causal structure. Thus, this study focused on searching the causal structure of certification criteria and verifying the reality of the model through simulation processing after developing a model. In conclusion, the development of dynamic evaluation method can be attributed to systematic evaluation for the criteria of Certification System.