• 산업공학
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• 제13권3호
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• pp.339-347
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• 2000

The use of the Web-based Simulation Environment (WBSE) provides a strong influence on supply chain simulations. A virtual supply chain simulation is available to evaluate strategies for reducing response time to customers and for shrinking the finished goods inventory along its supply chain. This paper presents the basic concepts and definitions of Web-Based Global Supply Chain Management (WBGSCM) simulation system. It also discusses the advantages of supply chain simulation modules integration. A Time Synchronization Mechanism (TSM) called Phased Bucket Scheme (PBS) is introduced as an approach of the distributed simulation modules integration.

• Ocean Systems Engineering
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• 제7권3호
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• pp.195-223
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• 2017

This paper presents 3D numerical simulations of a Free Standing Hybrid Riser under Vortex Induced Vibration, with prescribed motion on the top to replace the motion of the buoyancy can. The model is calculated using a fully implicit discretization scheme. The flow field around the riser is computed by solving the Navier-Stokes equations numerically. The fluid domain is discretized using the overset grid approach. Grid points in near-wall regions of riser are of high resolution, while far field flow is in relatively coarse grid. Fluid-structure interaction is accomplished by communication between fluid solver and riser motion solver. Simulation is based on previous experimental data. Two cases are studied with different current speeds, where the motion of the buoyancy can is approximated to a 'banana' shape. A fully three-dimensional CFD approach for VIV simulation for a top side moving Riser has been presented. This paper also presents a simulation of a riser connected to a platform under harmonic regular waves.

• 한국CDE학회논문집
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• 제13권3호
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• pp.209-216
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• 2008

This paper presents a novel approach to design evaluation of portable consumer electronic (PCE) products using augmented reality (AR) based tangible interaction and functional behavior simulation. In the approach, the realistic visualization is acquired by overlaying the rendered image of a PCE product on the real world environment in real-time using computer vision based augmented reality. For tangible user interaction in an AR environment, the user creates input events by touching specified regions of the product-type tangible object with the pointer-type tangible object. For functional behavior simulation, we adopt state transition methodology to capture the functional behavior of the product into a markup language-based information model, and build a finite state machine (FSM) to controls the transition between states of the product based on the information model. The FSM is combined with AR-based tangible objects whose operation in the AR environment facilitates the realistic visualization and functional simulation of the product, and thus realizes faster product design and development. Based on the proposed approach, a product design evaluation system has been developed and applied for the design evaluation of various PCE products with highly encouraging feedbacks from users.

• 한국시뮬레이션학회논문지
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• 제28권4호
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• pp.11-20
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• 2019

본 논문에서는 반도체 FAB에서의 OHT의 제어기를 검증하는 HIL(Hardware-In-the-Loop) 시뮬레이션 방법론을 제안한다. 반도체 FAB의 OHT 네트워크에는 수많은 OHT들이 동시에 운영될 수 있으므로 OHT 제어기에 대한 완벽한 검증은 물류 설비 안정성을 보장하는 데 매우 중요하다. 제어기는 정상적인 상황에 대해서 뿐 아니라 예측하기 힘든 비정상적인 상황에 대해서도 고려하여 설계되어야 한다. 따라서 본 연구에서는 제어기의 검증을 위해 비정상 상황을 생성할 수 있는 레일 네트워크와 OHT를 포함한 가상 환경을 사용하는 HIL 시뮬레이션 방법론을 제안한다. 제안되는 HIL 시뮬레이션 방법은 구현되었고, 다양한 예제를 통해 테스트 되었다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 춘계학술대회논문집
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• pp.253-258
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• 2002

This paper proposes a methodology for development of protocol models. The methodology attempts to employ two modeling environments in models development, NS2 and DEVSim++, which will interoperate during simulation. NS2 is a widely used network simulator in protocol research, which employs an informal modeling approach. Within the approach time and state information of protocol models are not explicitly described, thus being hard to validate model. On the other hand the DEVS formalism is a mathematical framework for modeling a discrete event system in a hierarchical, modular manner. In DEVS, model's time and state information is described explicitly, By using DEVS formalism, models can easily be validated and errors in the modeling stage can be reduced. However, the DEVS simulator, DEVSim++, supports a small amount of models library which are required to build simulation models of general communication network. Although NS2 employs an informal modeling approach and models validation is difficult, it supports abundant models library validated by experimental users. Thus, combination of DEVS models and NS2 models may be an effective solution for network modeling. Such combination requires interoperation between DEVSim++ simulator and NS2 simulator. This paper develops an environment for such interoperation. Correctness and effectiveness of the implemented interoperation environment have been validated by simulation of UDP and TCP models.

• 한국CDE학회논문집
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• 제12권2호
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• pp.87-94
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• 2007

The functional behavior of a consumer electronic product is nearly all expressed with human-machine interaction (HMI) tasks. Although physical prototyping and computer aided design (CAD) software can show the appearance of the product, they cannot properly reflect its functional behavior. In this paper, we propose an approach to virtual prototyping (VP) that incorporates HMI functional simulation into virtual reality techniques in order to enables users to capture not only the realistic look of a consumer electronic product but also its functional behavior. We adopt state transition methodology to capture the HMI functional behavior of the product into a state transition chart, which is later used to construct a finite state machine (FSM) for the functional simulation of the product. The FSM plays an important role to control the transition between states of the product. We have developed a VP system based on the proposed approach. The system receives input events such as mouse clicks on buttons and switches of the virtual prototype model, and it reacts to the events based on the FSM by activating associated activities. The system provides the realistic visualization of the product and the vivid simulation of its functional behavior using head-mounted displays (HMD) and stereo speakers. It can easily allow users to perform functional evaluation and usability testing. A case study about the virtual prototyping of an MP3 player is given to show the usefulness of the proposed approach.

• 한국항공운항학회지
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• 제18권2호
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• pp.23-34
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• 2010

After analyzing each procedure from standard instrument procedures used at Incheon International Airport, which is believed to have caused noise problems in and around Ganghwa island, we came to a conclusion that some Standard Instrument Departure Procedures and Standard Instrument Approach Procedures need to be revised, and therefore we made some propositions with regard to noise abatement procedures(CDA, RNAV approach etc.). Additionally, we evaluated viability of the proposed flight procedures by conducting a number of demonstrations with use of flight simulation.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1807-1816
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• 2020

In this work, a Gaussian Process (Kriging) approach is proposed to provide efficient dose mapping for complex radiation fields using limited number of responses. Given a few response measurements (or simulation data points), the proposed approach can help the analyst in completing a map of the radiation dose field with a 95% confidence interval, efficiently. Two case studies are used to validate the proposed approach. The First case study is based on experimental dose measurements to build the dose map in a radiation field induced by a D-D neutron generator. The second, is a simulation case study where the proposed approach is used to mimic Monte Carlo dose predictions in the radiation field using a limited number of MCNP simulations. Given the low computational cost of constructing Gaussian Process (GP) models, results indicate that the GP model can reasonably map the dose in the radiation field given a limited number of data measurements. Both case studies are performed on the nuclear engineering radiation laboratories at the University of Sharjah.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제3권1호
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• pp.112-120
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• 2003

This paper reports the development work carried out in respect of a proposed application of Neural Network approach for the Korean Next generation Reactor (KNGR) now referred as APR-1400. The emphasis is on establishing the methodology and the approach to be adopted towards realizing this application in the next generation reactors. Keeping in view the advantages and limitation of Artificial Neural Network Approach, the role of ANN has been limited to plant status or to be more precise plant transient monitoring. The simulation work carried out so far and the results obtained shows that artificial neural network approach caters to the requirements of plant status monitoring and qualifies to be incorporated as a part of proposed operator support systems of the referenced nuclear power plant.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1437-1440
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• 2007

Many hydroclimatic time series are marked by interannual and longer quasi-period features that are associated with narrow band oscillatory climate modes. A time series modeling approach that directly considers such structures is developed and presented. The essence of the approach is to first develop a wavelet decomposition of the time series that retains only the statistically significant wavelet components, and to then model each such component and the residual time series as univariate autoregressive processes. The efficacy of this approach is demonstrated through the simulation of observed and paleo reconstructions of climate indices related to ENSO and AMO, tree ring and rainfall time series. Long ensemble simulations that preserve the spectral attributes of the time series in each ensemble member can be generated. The usual low order statistics are preserved by the proposed model, and its long memory performance is superior to the direction application of an autoregressive model.