• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.453-458
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• 2001

A mobile agent is an autonomous software agent capable of moving from one computer to another while performing its tasks. We view the agent as a discrete event system in the view of its computation and communication. This paper presents a methodology far modeling and simulation of such a mobile agent system as a discrete event system. The methodology is based on the Mobile Discrete Event System Specification (MDEVS) formalism and the associated simulation environment AgentSim which are previously developed by the authors. Within the methodology an atomic model represents dynamics of a mobile agent; a coupled model is modeled as mobile agent servers for representation of structural changes between atomic agents. Being based on the object-oriented environment the modeling methodology exploits inheritance of basic classes AtomicModel and CoupledModel provided by AgentSim.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.484-484
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• 2001

The sophistication of current software applications results in the increasing cost fur software development time. The component-based software development framework is proposed to overcome the difficulty and time-consuming requirements by modularity and reusability. As is the general software case, a component-based simulation framework encourages the reusability of the real system model based on the modularity of the applied simulation methodology. This paper presents a component-based simulation environment that is based on the DEVS/COM run-time infrastructure. The DEVS (Discrete Event System Specification) formalism provides a formal modeling and simulation framework for the generic dynamic systems [1] and Microsoft's COM (Component Object Model) is one of the strongest competitor fur the component standard. The reusability by the DEVS/COM simulation environment saves model development time remarkably and component technology make simulator itself to be a subparts of real application.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.177-184
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• 1998

최근까지 개발된 시뮬레이션 소프트웨어를 검토 정리한 후, 시뮬레이션 소프트웨어와 그 모델과의 연관성을 파악하기 위하여 총체적인 시뮬레이션 모델을 관찰하였으며, 시뮬레이션 소프트웨어의 유연성에 대한 근원을 시스템 모듈식 접근 방법을 통하여 추적하였다. 실존 시스템, 모델, 그리고 소프트웨어 시스템과의 관계를 조사한 결과 시뮬레이션 소프트웨어의 주요한 성능 척도는 flexibility와 accuracy라는 것이 밝혀졌다. 객체지향 시뮬레이션 소프트웨어의 metrics와 formalism의 모델을 개발하였으며, 이것은 유연한 객체지향적 시뮬레이션 소프트웨어 구조를 디자인하는데 근본 방침을 제시한다. 끝으로 앞에서 개발한 모델을 기초로, 유연한 객체지향적 시뮬레이션 소프트웨어 시스템을 분석하였다.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.233-242
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• 2014

A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.670-673
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• 2000

This paper attempt analysis and computer simulation of dynamics of a set of dual multi-joint fingers with soft-deformable tips which are grasping. Firstly, a set of differential equation describing dynamics of the fingers and object together with geometric constraint of tight area-contacts is formulated by Euler-Lagrange's formalism. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of area-contacts of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for overall system of differential-algebraic equations is presented. Finally, simulation results are shown and the effects of geometric constraints of area-contact is discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.543-546
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• 2003

We studied the dielectric layer effect on the electro-optical (EO) properties of liquid crystal (LC) devices together with numerical simulations. Recently, it has been reported that the surface dielectric layer affects significantly the EO performances of LC microlens arrays and wide-viewing LC displays. it is found that the operation voltage of the LC device decreases with increasing the dielectric constant or with decreasing the thickness of the dielectric polymer layer. The experimental data agree well with theoretical results predicted in a simple dielectric model within the continuum formalism.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.162-172
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• 1993

In the present paper, the overall state of the arts of ice mechanics which is the most typical research topic of the artic engineering field was studied. And also, ice loads genrated by ice-structure interaction were estimated using numerical approach. The effects of viscous property of ice sheets to the ice load were investigated. The time dependent deformation behaviors of ice was modeled by visco-plastic problem using the finite element formalism. Constitutive model representing the material properties of ice was idealized by comblned rheological model with Maxwell and Voigt models. Numerical calculations for the bending and crushing behavior of ice sheet which are the most typical interaction modes between ice sheets and structures were carried out. The time dependent viscous behaviors of ice sheets interaction forces acting on structures were analyzed and the results were studied in detail.

• ETRI Journal
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• v.22 no.3
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• pp.19-26
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• 2000

We describe a detailed numerical scheme to calculate electron transport in quantum wires using the Green function formalism combined with tight-binding orbital basis. As an example of the application, we study the electron transport in a Si nanowire containing a finite potential barrier. The effects of nonzero bias, temperature, and disorder on the barrier-induced oscillatory conductance are investigated within the context of coherent transport model. The oscillatory behavior of the conductance as a function of the Fermi energy is found to be highly sensitive to sample disorder and limited to a very low temperature and a small bias range.

• Journal of the Korean Society of Costume
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• v.53 no.7
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• pp.125-137
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• 2003

This study is to explore the Post-modern fashion image appeared in the costumes of the movie $\ulcorner$Matrix2-Reloaded$\lrcorner$, which is believed to adapt successfully the Postmodernism ideas on screen. From this study, we can find that the movie costumes express certain formative characteristics considerably affected by the contemporary fashion trends such as Minimalism, Formalism, Futurism, Ethno-eclecticism, Asexualism. These are mostly common tendencies aroused in the complex and pluralistic circumstances of Postmodernism where many diverse values are equally regarded. Finally, the 5 trends lead to represent the following symbolic meanings with entanglement in multiplex ways, that is Virtual Reality, Mechanic Artificiality, Human Dignity, Mysticism, Multi-Culturism, and Nonsexuality to create a strong unified imagery and style in that Post-modern movie.

• Journal of Mechanical Science and Technology
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• v.16 no.5
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• pp.710-719
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• 2002

This study investigates a nonlinear inverse convection problem for a laminar-forced convective flow between two parallel plates. The upper plate is exposed to unknown heat flux while the lower plate is insulated. The unknown heat flux is determined using temperature measured on the lower plate. The thermophysical properties of the fluid are temperature dependent, which renders the problem nonlinear. The sequential gradient method is applied to this nonlinear inverse problem in order to solve the problem efficiently. The function specification method is incorporated to stabilize the sequential estimation. The corresponding adjoint formalism is provided. Accuracy and stability have been examined for the proposed method with test cases. The tendency of deterministic error is investigated for several parameters. Stable solutions are achieved eve]1 with severely impaired measurement data.