• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.12-16
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• 2007

A dynamic model of proton exchange membrane fuel cell(PEMFC) system is designed to understand the performance of the PEMFC in residential power generator(RPG) over various balance of plant(BOP) options. In particular, since the performance of PEMFC system should be optimized for given operating ranges, it is necessary to design suitable BDP components which can support the operating ranges. The objective of this study is to develop a dynamic system model for the study of PEMFC performance over various BOP options. Therefore, a dynamic model is composed of a PEMFC stack model, a water management system model, a thermal management system model and a fuel/air supply model and the model is integrated under SIMULINK(R)environment. Basic simulation results will be presented.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.672-677
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• 2000

This paper compares the two kinds of friction model. The first model is classical stick/slip model. In the stick/slip model, the system is treated to have two different states, namely, stick state or slip state. The second one is continuous model developed by Dahl et. al, namely, Extended Dahl's model. Each model has unique properties, and can be best useful when it is applied on the appropriate system. In this paper, each model is applied on the simple two-block system and the complex automatic transmission system. And the simulation result including simulation accuracy and time required are compared.

• 한국CDE학회지
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• 제3권3호
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• pp.36-45
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• 1997

This paper presents the research on the development of Generic modeling system as a 3D CAD customizing system for the elevator design. This system enables to create a generic model which gives birth to many models. The generic model is expressed as a non-scale model or a standard model in this paper. Using the parametric design techniques, all their relationships are explicitly represented in the tables, not represented in implicit embedded coding. Owing to this method, designers can easily extend the generic model to contain more model families. All parametric relations are stored in relational database. A designer can retrieve various models from a generic model automatically, by using some key input values.

• Coupled systems mechanics
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• 제11권1호
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• pp.43-54
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• 2022

In order to analyse the thermal performance of battery systems in electric vehicles complex simulation models with high computational cost are necessary. Using reduced order methods, real-time applicable model can be developed and used for on-board monitoring. In this work a data driven model of the cooling plate as part of the battery system is built and derived from a computational fluid dynamics (CFD) model. The aim of this paper is to create a meta model of the cooling plate that estimates the temperature at the boundary for different heat flow rates, mass flows and inlet temperatures of the cooling fluid. In order to do so, the cooling plate is simulated in a CFD software (ANSYS Fluent ®). A data driven model is built using the design of experiment (DOE) and various approximation methods in Optimus ®. The model can later be combined with a reduced model of the thermal battery system. The assumption and simplification introduced in this paper enable an accurate representation of the cooling plate with a real-time applicable model.

• 대한토목학회논문집
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• 제4권3호
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• pp.63-74
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• 1984

System Dynamics는 OR 또는 Industrial Engineering의 수량적(數量的)이고 이론적(理論的)인 분석방법(分析方法) 위에 Management 의사결정(意思決定) 과정(過程) 도입(導入)한 System 적(的) 방법(方法)이다. 그러므로 사회(社會) System의 장래예측(將來豫測)과 아울러 대안(代案)의 검토(檢討) 및 선택방법(選擇方法)으로서는 가장 유효(有効)한 수리적(數理的) 방법(方法)이라고 할 수 있다. 경제기초가설(經濟基礎假說)에 의거(依據)하여 개발(開發)된 도시활동(都市活動)의 생성(生成) Model을 System Dynamics 화(化)하여 토지이용(土地利用)-교통(交通) System Dynamics Model을 구축(構築)하였다. 그리고 대구지성(大邱地城)의 적용례(適用例)에 의(依)하여 Model의 유효성(有効性)을 검토(檢討)하였으며 그 결(結果) 유의(有意)하였다.

• 한국경영과학회지
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• 제36권4호
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• pp.1-16
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• 2011

It is important not only to introduce the C4I(Command and Control, Communication, Computer, Intelligence) system for realizing the NCW(Network Centric Warfare) but also to evaluate the synergistic effect by the C4I system. However, the study effort for evaluating the system's synergistic effect is insufficient compared with introducing the system. Therefore, in this paper, we proposed a model that measures the synergistic effect of combat power by the warfare information system. To measure the synergistic effect of warfare information system, the network power must be considered, so we also proposed a new methodology for measurement of network power based on SNA(Social Network Analysis), not Metcalfe's law. A model we proposed is a model that measures the raised combat power by the network effectiveness. The methodology and model we proposed in this paper will be used usefully to analyze the practical effect of constructing future warfare information system.

• 대한전기학회논문지:전력기술부문A
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• 제48권6호
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• pp.747-752
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• 1999

In the fast sampling limit, the delta operator model tends to the analog system model. This fundamental property of the delta operator model unifies continuous and discrete time control system. In this paper, we study robust linear optimal model following servo system in the presence of disturbances and parameter perturbations. A technique to directly design the generalized differential operator based unified control system that convers both differential operator based continuous time and delta operator based discrete time case is presented. The quadratic criterion function for a linear system is used to design the robust unified servo control. The characteristics of the proposed servo system are analysed and simulated to verify the robustness.

• 산업경영시스템학회지
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• 제30권3호
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• pp.158-164
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• 2007

Supply Chain Management (SCM) system is a critical investment that can affect the competitiveness and performance of a company. Selection of a right SCM system is one of the critical issues. This paper presents the characteristic factors of SCM system and a Fuzzy AHP (Analytic Hierarchy Process) based decision-making model for SCM system evaluation and selection. This study focuses on quantitative factors, applying the fuzzy concept to various evaluative factors. The proposed model can systematically construct the objectives of SCM system selection to achieve the business goals. A empirical example demonstrates the feasibility of the proposed model and the model can help a company to make better decision-making in the SCM system selection problem.

• International Journal of Railway
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• 제3권2호
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• pp.46-53
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• 2010

Electric railroad systems consist of rolling stock, track, signal and catenary system. In the catenary system, one of the most important factors is the impedance according to the design and characteristic. Before the catenary system is designed, the impedance should be precedently researched. The railroad catenary system is complex system which is composed by five conductors. The five conductors classify up and down feeders, up and down contact wire group, rail group. Therefore, we should compose the catenary system of the equivalent five-conductors model. In this paper, we suggest a geometrical model and a equivalent conductor model by using geometric mean radius of five conductors in the catenary system. Also, we calculate demanded parameter values in the model. By using those, line constants of five conductors are analyzed by applying the equivalent method called as the condensed joint matrix.

• 한국시스템다이내믹스연구
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• 제8권2호
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• pp.209-234
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• 2007

Recently, balanced scorecard is widely used in the public sector as well as in the private sector. Balanced scorecard system of a particular hospital is a very useful tool in the sense that it shows various measures for the management including the traditional financial measures. However, since it does not show the impact of action items, managers have to analyze his potential decisions. On the other hand, a system dynamics model for the management of a hospital can be used to predict future management status. In this paper, a balanced scorecard system with a system dynamics model is developed for a small sized hospital, and the feasibility and applicability of the system have been tested. It turns out the combination of the balanced scorecard and system dynamics technique can be comprised each other. The balanced scorecard system can take advantage of the data forecasted by the system dynamics model including the implementation of action items taken today. On the other hand, the key performance indicators and action items from the balanced scorecard system provide guidelines the scope and direction of the system dynamics model. The additional efforts of developing a system dynamics model are well compensated by the additional colorful functionalities of the system. This paper also covers the future research areas for the combined system to be more effectively developed.