• 한국시뮬레이션학회논문지
• /
• 제2권1호
• /
• pp.125-133
• /
• 1993

A statistical method is described for estimation of the unknown constants in a theory using both of the computer simulation data and the real experimental data, The best linear unbiased predictor based on a spatial linear model is fitted from the computer simulation data alone. Then nonlinear least squares estimation method is applied to the real experimental data using the fitted prediction model as if it were the true simulation model. An application to the computational nuclear fusion devices is presented, where the nonlinear least squares estimates of four transport coefficients of the theoretical nuclear fusion model are obtained.

• 대한산업공학회지
• /
• 제32권4호
• /
• pp.373-381
• /
• 2006

This paper considers a scheduling problem for a hybrid flowshop with dynamic order arrival. A hybrid flowshop is an extended form of a flowshop, which has serial stages like a flowshop but there can be more than one machine at each stage. In this paper, we propose a new method for the problem of scheduling with the objective of minimizing mean tardiness of orders which arrive at the shop dynamically. The proposed method is based on the list scheduling approach, however we use a more sophisticated method to prioritize lots unlike dispatching rule-based methods. To evaluate the performance of the proposed method, a simulation model of a hybrid flowshop-type production system is constructed. We implement well-known dispatching rules and the proposed methods in the simulation model. From a series of simulation tests, we show that the proposed methods perform better than other methods.

• 한국시뮬레이션학회논문지
• /
• 제29권2호
• /
• pp.63-72
• /
• 2020

다양한 무기체계 중 대표적인 지상 무기체계인 전차는 각국의 핵심 전력 중 하나로, 전차의 운용 개념과 효과도 분석을 통해 과학적 분석 기반의 비용 효과적인 연구개발을 할 수 있다. 이를 위하여 교전 시뮬레이션 기술이 활용될 수 있는데, 전차 무기체계를 모델링함에 있어 전차의 기동, 통신 등과 같은 물리적인 요소뿐만 아니라, 운용교리를 반영한 효과분석을 위하여 전차장 등의 의사결정을 모델링하는 논리 모델도 중요하다. 이 논문에서는 무기체계 통합시뮬레이션 소프트웨어(AddSIM)에서 제공하는 무기체계 모델의 표준 아키텍처인 기본체계모델(Base System Model, BSM)에 맞추어 전차 교전 시뮬레이션에 필요한 전차 BSM 설계방법에 대하여 논한다. 특히 논리 모델을 인간 의사결정 모델에 근거하여 세분화하였으며, DEVS 형식론이라는 수학적 형식론에 기반한 정형적인 모델링 방법으로 모델링하였다. 그 결과 전차 BSM을 계층적이고 모듈화된 형태로 제안하였다. 제안하는 방법은 향후 우리 군의 전차 운용 개념 연구와 전차의 효과분석 등에 활용될 것으로 기대된다.

• Wind and Structures
• /
• 제15권3호
• /
• pp.223-245
• /
• 2012

Multivariate simulation is necessary for cases where non-Gaussian processes at spatially distributed locations are desired. A simulation algorithm to generate non-Gaussian wind pressure fields is proposed. Gaussian sample fields are generated based on the spectral representation method using wavelet transforms method and then mapped into non-Gaussian sample fields with the aid of a CDF mapping transformation technique. To illustrate the procedure, this approach is applied to experimental results obtained from wind tunnel tests on the domes. A multivariate Gaussian simulation technique is developed and then extended to multivariate non-Gaussian simulation using the CDF mapping technique. It is proposed to develop a new wavelet-based CDF mapping technique for simulation of multivariate non-Gaussian wind pressure process. The efficiency of the proposed methodology for the non-Gaussian nature of pressure fluctuations on separated flow regions of different rise-span ratios of domes is also discussed.

• 한국시뮬레이션학회논문지
• /
• 제9권4호
• /
• pp.41-50
• /
• 2000

We have many simulation constraints to meet as a modeled system becomes large and complex. Real-time simulations are the examples in that they are constrained by certain non-function constraints (e.g., timing constraints). In this paper, an enhanced hierarchical modeling methodology is proposed to efficiently deal with constraint-simulations. The proposed modeling method enhances hierarchical modeling methods to provide multi-resolution model. A simulation model is composed by determining the optimal level of abstraction that is guaranteed to meet the given simulation constraints. Four modeling activities are defined in the proposed method: 1) Perform the logical architectural design activity to produce a multi-resolution model, 2) Organize abstraction information of the multi-resolution model with AT (Abstraction Tree) structure, 3) Formulate the given constraints based on U (Integer Programming) approach and embrace the constraints to AT, and 4) Compose a model based on the determined level of abstraction with which the multi-resolution model can satisfy all given simulation constraints. By systematically handling simulation constraints while minimizing the modeler's interventions, we provide an efficient modeling environment for constraint-simulations.

• 전자공학회논문지B
• /
• 제31B권6호
• /
• pp.63-70
• /
• 1994

In this paper, we propose a fault simulation method based on primary output in combinational circuit. In the deterministic test pattern generation, each test pattern is genterated incrementally. The test pattern is applied to the primary inputs of circuit under test to simulate faults. We detect the faults with respect to each primary output. The fault detection with resptect to each primary output is reflected by the corresponding bit in the detection words, and efficient fault detection for the reconvergent fan-out stem is achieved with dynamic fault propagation. As an experimental result of the fault simulation with our method for the several bench mark circuits, we illustrated the good performance showing that the number of gates to be activated is much reduced as compared with other method which is not based on primary output.

• KIEAE Journal
• /
• 제15권5호
• /
• pp.95-105
• /
• 2015

Purpose: This paper presents a framework development for BIM (Building Information Modeling)-based OOPM (Object-Oriented Physical Modeling) for Building Thermal Simulation. The framework facilitates decision-making in the design process by integrating two object-oriented modeling approaches (BIM and OOPM) and efficiently providing object-based thermal simulation results into the BIM environment. Method: The framework consists of a system interface between BIM and OOPM-based building energy modeling (BEM) and the visualization of simulation results for building designers. The interface enables a BIM models to be translated into OOPM-based BEM automatically and the thermal simulation from the created BEM model immediately. The visualization module enables the simulation results to be presented in BIM for building designers to comprehend the relationships between design decisions and the building performances. For the framework implementation, we utilized the Modelica Buildings Library developed by the Lawrence Berkeley National Laboratory as a thermal simulation solver. We also conducted an experiment to validate the framework simulation results and demonstrate our framework. Result: This paper demonstrates a new methodology to integrate BIM and OOPM-based BEM for building thermal simulation, which enables an automatic translation BIM into OOPM-based BEM with high efficiency and accuracy.

• 한국시뮬레이션학회논문지
• /
• 제18권2호
• /
• pp.57-64
• /
• 2009

물리적 기반의 다이내믹 시뮬레이션에 있어서 안정적이고 효율적인 제한 시스템은 매우 중요한 요소 중 하나이다. 본 논문은 기존에 널리 사용되고 있는 제한 시스템들(Lagrange Multiplier method, Baumgarte stabilization method, Post-stabilization Method, Implicit constraint enforcement method, Fast projection method)에 대한 분석과 평가를 통해 제한 시스템을 사용하고자 하는 사용자들에게 적절한 선택을 할 수 있는 지침을 제공하고자 한다. 본 논문은 기존의 제한 방법들에 대한 수학적 수식들이 설명되어 있고, 제한 오차 비교, 계산 비용, 동적 움직임 분석 등을 통해 기존 제한 시스템들 각각에 대한 평가를 제공한다.

• Interaction and multiscale mechanics
• /
• 제2권4호
• /
• pp.353-374
• /
• 2009

A new seamless multiscale simulation was developed for coupling the continuum model with its molecular dynamics. Kriging-based Finite Element Method (K-FEM) is employed to model the continuum base of the entire domain, while the molecular dynamics (MD) is confined in a localized domain of interest. In the coupling zone, where the MD domain overlaps the continuum model, the overall Hamiltonian is postulated by contributions from the continuum and the molecular overlays, based on a quartic spline scaling parameter. The displacement compatibility in this coupling zone is then enforced by the Lagrange multiplier technique. A multiple-time-step velocity Verlet algorithm is adopted for its time integration. The validation of the present method is reported through numerical tests of one dimensional atomic lattice. The results reveal that at the continuum/MD interface, the commonly reported spurious waves in the literature are effectively eliminated in this study. In addition, the smoothness of the transition from MD to the continuum can be significantly improved by either increasing the size of the coupling zone or expanding the nodal domain of influence associated with K-FEM.

• 항공우주시스템공학회지
• /
• 제15권4호
• /
• pp.75-84
• /
• 2021

A novel robot-operating-system-based flight and mission state communication node for X-Plane 11 flight control simulation environments and its simulation results were discussed. Although the proposed communication method requires considerable implementation steps compared with the conventional MATLAB/Simulink-based User Datagram Protocol (UDP) block utilization method, the proposed method enables a direct comparison of cockpit-view images captured during flight with the flight data. This comparison is useful for data acquisition under virtual environments and for the development of flight control systems. The fixed/rotary-wing and ground terrain elements simulated in virtual environments exhibited excellent visualization outputs, which can overcome time and space constraints on flight experiments and validation of missionary algorithms with complex logic.