• International Journal of CAD/CAM
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• 제2권1호
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• pp.39-44
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• 2002

This paper presents a structure and architecture of an integrated simulation method (ISM) to meet the requirements of virtual factory engineering (VFE). Combining CAD, VR and discrete event simulation techniques, the ISM provides static and dynamic simulation functions for implementation of VFE throughout the lifecycle. The static simulation can be used to evaluate the factory layout. The dynamic simulation enables us to evaluate ergonomics of factory, process performance of production system, feasibility of production plan and operation of factory, and to train operators safely, which cover the whole VFE lifecycle. The principles of the key techniques of VFE, including virtual factory data management system (VFDMS), static and dynamic simulation, are also discussed. To demonstrate and validate the ISM, a case study has been carried out in an assembly factory.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1996년도 춘계학술대회
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• pp.15-15
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• 1996

A shop floor control system (SFCS) is the central part of a CIM system used to control the activities of several pieces of manufacturing equipment (e.g., NC machines, robots, conveyors, AGVs, AS/RS). The SFCS receives orders and related process plans, and then performs selecting a specific process routing, allocating resources, scheduling the workpieces, downloading the processing instructions (e.g., RS-274 instructions for NC machines, VAL II programs for robot), monitoring the progress of activities, detecting and recovering from errors, and preparing reports on the status of the manufacturing system. Simulation has been utilized in discovering control policies used for resolving shop floor be control problems such as resource contentions, part dispatching, deadlock. The simulation model must be designed to respond to real-time data coming from a shop floor. However, to rapidly build a realtime simulation model of SFCS cannot be easily accomplished. This talk is to address an automatic program generator of discrete event simulation model for shop floor control from process plans and resource models. The program generator is capable of constructing complete discrete simulation models for multi-product and multi-stage flexible manufacturing systems.

• 한국시뮬레이션학회논문지
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• 제7권1호
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• pp.69-83
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• 1998

In this paper, we present the results of simulation by running parallel VHDL simulation on typical MPP(Massively Parallel Processor) systems such as IBM SP2 and SGI Origin 2000. Parallel simulation uses the synchronous protocol and parallel program is implemented using MPI(Message Passing Interface) based on message passing model, so that it can urn on any parallel programming environment which supports MPI, a standard communication library. And then GVT(Global Virtual Time) computation for parallel simulation is based on the global broadcasting with MPI＿Bcast(), which is a standard function in MPI and piggybacking. Our benchmark exhibits that as size of VHDL grows, the parallel simulation has a better performance compared with the sequential simulation. In addition, we also show the results of comparison between IBM SP2 and SGI Origin 2000 by applying the same application to those indirectly.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1359-1363
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• 2009

The object of this research is to develop a simulation system for earthmoving operations in consideration of the impact of congestion in-between equipment and existing traffic flow around the site. The congestion in-between equipment and traffic flow affect work productivity. The conventional discrete event simulation, however, has limitations in simulating the flow of construction equipment. To consider the impact of congestion in-between equipment and existing traffic flow, in this paper, a multi-agent based simulation model that can realize characteristics of truck behavior more accurately to consider the impact of congestion was proposed. In this simulation model, multiple agents can identify environmental changes and adapt themselves to the new environment. This modeling approach is a better choice for this problem since it describes behavioral characteristics of each agent by sensing changes in dynamic surroundings. This study suggests a detailed system design of the multi-agent based simulation system.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.579-586
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• 2009

4D simulation integrates the 3 dimensional model of a building with the construction schedule, and it leads to the possibility of virtually checking the construction process and the building itself in advance. However, the existing problem of 4D simulation is the difference between the demands of architects, engineers, and construction site workers in 4D simulation. This study suggests the possible way to enhance the availability of 4D simulation, considering more the practical demands from the construction site. In order to conduct this study, we build a 3D BIM model of a business-residential complex and link the model with the pre-defined construction schedule in order to make a 4D simulation. This study concludes with the optimized 4D simulation methodology based on BIM model considering the demands in perspective of the construction site. It would contribute to the harmonic collaboration among architects, engineers, and labors in the construction site when using 4D simulation based on BIM model.

• Journal of Computing Science and Engineering
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• 제3권2호
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• pp.73-87
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• 2009

A hybrid system is a dynamical system in which states can be changed continuously and discretely. Simulation based on numerical methods is the widely used technique for analyzing complicated hybrid systems. Numerical simulation of hybrid systems, however, is subject to two types of numerical errors: truncation error and round-off error. The effect of such errors can make an impossible transition step to become possible during simulation, and thus, to generate a simulation behavior that is not allowed by the model. The possibility of an incorrect simulation behavior reduces con.dence in simulation-based analysis since it is impossible to know whether a particular simulation trace is allowed by the model or not. To address this problem, we define the notion of Instrumented Hybrid Automata (IHA), which considers the effect of accumulated numerical errors on discrete transition steps. We then show how to convert Hybrid Automata (HA) to IRA and prove that every simulation behavior of IHA preserves the discrete transition steps of some behavior in HA; that is, simulation of IHA is sound with respect to HA.

• Wind and Structures
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• 제18권5호
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• pp.549-566
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• 2014

In spite of progress in the numerical simulation of typhoon wind field in atmospheric boundary layer (ABL), using typhoon wind field model in conjunction with Monte Carlo simulation method can only accurately evaluate typhoon wind field over a general terrain. This method is not enough for a reliable evaluation of typhoon wind field over the actual complex terrain with surface roughness and topography variations. To predict typhoon wind field over the actual complex terrain in ABL, a hybrid numerical simulation method combined typhoon simulation used the typhoon wind field model proposed by Meng et al. (1995) and CFD simulation in which the Reynolds averaged Navier-Stokes (RANS) equations and k-${\varepsilon}$ turbulence model are used. Typhoon wind filed during typhoon Dujuan and Imbudo are simulated using the hybrid numerical simulation method, and compared with the results predicted by the typhoon wind field model and the wind field measurement data collected by Fugro Geotechnical Services (FGS) in Hong Kong at the bridge site from the field monitoring system of wind turbulence parameters (FMS-WTP) to validate the feasibility and accuracy of the hybrid numerical simulation method. The comparison demonstrates that the hybrid numerical simulation method gives more accurate prediction to typhoon wind speed and direction, because the effect of topography is taken into account in the hybrid numerical simulation method.

• 한국국방경영분석학회지
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• 제26권2호
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• pp.101-119
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• 2000

US DoD designated the High LEvel Architecture (HLA) as the standard technical architecture for all military simulation since 1996. HLA will supercede the current Distributed Interactive Simulation(DIS) and Aggregated LEvel Simulation Protocol(ALSP) methods by no funds for developing/modifying non-HLA compliant simulations. The new architecture specifies Rules which define relationships among federation components, an Objects Model Template which species the form which simulation elements are described, and an Interface Specification which describes the way simulations interact during operations. HLA is named as standard architecture in NATO, Australia and many other militaries. Also, it will be IEEE standard in the near future. It goes without saying that ROK military whose simulation models are almost from US must be prepared in areas such as ROK-US combined exercise, training, weapon system acquisition, interface models with C4I system, OPLAN analysis, operations, and os on. In this paper, we propose several effective alternatives and issues for ROK Defense Modeling and Simulation under the transition of new HLA architecture. Those include secure the kernel of new simulation technology and develop our own conceptual model, RTI software, prototype federation for each service and aggregated one. In order to challenge the new simulation architecture effectively, we should innovate our current defense modeling and simulation infrastructure such s manpower, organization, budget, research environment, relationships among academia and industry, and many others.

• 한국시뮬레이션학회논문지
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• 제24권4호
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• pp.51-58
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• 2015

국방 M&S 분야에서 모의 기반 획득 방법이 필수적인 정책으로 인식되면서 M&S 관련 프레임워크 및 솔루션들이 개발되어 현업에 적용되고 있다. 이러한 프레임워크나 솔루션을 기반으로 개발되는 시뮬레이션 시스템은 공통적으로 통제부, 시나리오 생성부, 모의부로 나눌 수 있고 각 파트가 수행하는 기능은 시뮬레이션 시스템에 관계 없이 유사하다. 그럼에도 불구하고 시뮬레이션 시스템마다 각기 다른 시뮬레이션 생성 기능을 구현함으로써 시스템 개발 비용이 증가하는 문제를 겪고 있다. 이러한 문제를 해결하기 위하여 목적 시뮬레이션 시스템의 모의 내용과 관계 없이 재사용이 가능한 시뮬레이션 시나리오 프레임워크를 개발하였으며 이를 통해 다양한 시뮬레이션 시스템을 효과적으로 개발할 수 있었다. 본 연구에서는 QUEST를 기반으로 하여 모의 모델에 관계없이 재사용 가능한 시뮬레이션 시나리오 프레임워크의 구조와 기능 요소들에 대해 설명한다.

• 대한조선학회논문집
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• 제46권6호
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• pp.641-649
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• 2009

There were many simulation models that made for validation of industrial environment and estimate of efficiency to be constructed. And there will be more simulation models made for same reason, too. Already, there have been a lot of simulation models in industry field and scholar labs. To reuse these simulation models, it is necessary to find common properties and make the high abstract simulation model. Based on this idea, this study shows to define the high abstract simulation model to be able to specialize in need and to make the software framework for connecting the specific simulation model to the abstract model. And it is held up as the example that applying the simulation framework to the Ship Panel Block shop simulation model.