• 한국시뮬레이션학회논문지
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• 제22권4호
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• pp.1-9
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• 2013

국방과학연구소는 해군 전투실험을 위한 시뮬레이션 통합개발환경(QUEST)을 개발하였으며 본 논문은 QUEST의 수중교전 시뮬레이션을 응용을 위한 해군무기체계 모델 라이브러리 개발에 대하여 기술한다. 모델은 기본적으로 함정 및 무장체계 간의 수중교전 효과도 및 전술 개발 목적으로 개발되었다. 수중교전 임무공간과 기존 운용모델 기능 분석을 통하여 표준 모델구조를 정립하고 구성 컴포넌트를 개발하였다. 각각의 컴포넌트는 무기체계 구성부의 기능을 잘 정의한 표준화된 체계, 부체계, 알고리듬 모델이며 모델간 표준 인터페이스를 정의하였다. 모델 라이브러리를 이용하여 사용자는 최소한의 도메인지식으로 기존 모델을 재사용하고 새로운 모델을 효율적으로 조립가능하며 사용자간에 모델을 공유하고 협업할 수 있다.

• 산업공학
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• 제21권4호
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• pp.418-434
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• 2008

This paper studied issues in decision making on the production control policy of a cathode plate manufacturing process in zinc refining plant. The present production system has a long lead time from raw materials (aluminum plate) to products (cathode plate) due to many WIP inventories. Because WIP inventories are stocked at each process and moved from one place to another frequently, they are the main cause of inefficiency in the process. In this paper, to solve this problem, several production control policies have been identified and studied. Several simulation models are used to compare the performances of these production control policies. The output lead time and WIP (Work In Process) of real production system are compared with those of simulation models. PUSH, CONWIP, DBR, KANBAN and CONWIP-DBR models have been used to simulate and review the optimized production control policy that achieves the target output quantities with decreased lead time and WIP. The simulation results of each production control policy show that CONWIP and CONWIP-DBR models are the good production control policy under the present production system. Especially in present production system, CONWIP with one parameter is easier control policy than CONWIP-DBR with two parameters. Therefore CONWIP has been selected as the best optimum production control policy. With CONWIP, lead time has been reduced by 97% (from 6,653 to 187 minute) and WIP has been reduced from 1,488 to 53, compared to the present system.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1995년도 추계학술대회발표논문집; 서울대학교, 서울; 30 Sep. 1995
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• pp.46-58
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• 1995

Although numerous distributed database design models and solution algorithms have been developed, very few have been validated. Validation is critical to the successful application of such models to distributed database design. In this paper, we develop a simulation system for distributed database design. We then analyze and validate an average response time model using simulation. The simulation results demonstrate that the average response time model is reasonably accurate.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.22-29
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• 2008

In order to improve the efficiency of a main transformer in a tilting train, the optimal operation of a cooling system is necessary. For the development of optimal control algorithms of a cooling system, mathematical models of a main transformer cooling system were developed. These include dynamic models of a main transformer, an oil pump, an oil cooler, a blower, and a pipe. Control algorithms for a blower and an oil pump were selected in order to identify the effectiveness of dynamic models. A simulation program was developed by using the developed dynamic models and the selected control algorithms. Simulation results showed good predictions of dynamic behaviors of a main transformer cooling system. Therefore, dynamic models, which were developed in this study, may be effectively used to develop control algorithms of a main transformer cooling system.

• 한국군사과학기술학회지
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• 제17권1호
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• pp.71-81
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• 2014

It is an important issue to evaluate the effectiveness of chemical warfare through modeling and simulation(M&S) technology. In this paper, we propose the M&S methodology and environment for the chemical warfare for effectiveness analysis. In detail, for modeling perspective, we propose three fundamental component models according to their behaviors, which are a chemical weapon, a detecting device system, and an engaging unit system. Among proposed models, the chemical weapon and the detecting device system models are represented by engineering-level system models, whereas the engaging unit system model are described as an engagement-level system model. For simulation perspective, we apply a hybrid simulation environment using High Level Architecture (HLA) to interoperate with the proposed engineering and engagement-level models. The proposed M&S methodology and environment enables to evaluate the effectiveness of the chemical warfare system considering the doctrines, the performance of device or weapon, and weather factors. To verify the efficiency of the proposed methodology and environment, we experimented three categorized case studies, which are related with those considering factors.

• 비파괴검사학회지
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• 제22권6호
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• pp.649-658
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• 2002

As an attempt to further improve the reliability and effectiveness of ultrasonic testing (UT), a two-dimensional numerical simulator of UT was developed. The simulator models the wave medium (or test object) using the mass-spring lattice model (MSLM) that consists of mass-points and springs. Some previous simulation results, obtained by using MSLM, are briefly reviewed in this paper, for propagation, reflection, and scattering of ultrasonic waves. Next, the models of transmitting and receiving piezoelectric transducers are introduced with some numerical results, which is a main focus of this paper. The UT simulator, established by combining the transducer models with the MSLM, was used to simulate many UT setups. In this paper, two simple setups are considered as examples, and their simulated A-scan signals are discussed. The potential of the MSLM, transducer models, and the UT simulator developed in this study to be used in the actual UT is confirmed.

• Journal of Korean Neurosurgical Society
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• 제65권4호
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• pp.489-498
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• 2022

Spatial insight into intracranial pathology and structure is important for neurosurgeons to perform safe and successful surgeries. Three-dimensional (3D) printing technology in the medical field has made it possible to produce intuitive models that can help with spatial perception. Recent advances in 3D-printed disease models have removed barriers to entering the clinical field and medical market, such as precision and texture reality, speed of production, and cost. The 3D-printed disease model is now ready to be actively applied to daily clinical practice in neurosurgical planning, simulation, and training. In this review, the development of 3D-printed neurosurgical disease models and their application are summarized and discussed.

• Genomics & Informatics
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• 제21권2호
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• pp.27.1-27.7
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• 2023

Recombination events complicate the evolutionary history of populations and species and have a significant impact on the inference of isolation-with-migration (IM) models. However, several existing methods have been developed, assuming no recombination within a locus and free recombination between loci. In this study, we investigated the effect of recombination on the estimation of IM models using genomic data. We conducted a simulation study to evaluate the consistency of the parameter estimators with up to 1,000 loci and analyze true gene trees to examine the sources of errors in estimating the IM model parameters. The results showed that the presence of recombination led to biased estimates of the IM model parameters, with population sizes being more overestimated and migration rates being more underestimated as the number of loci increased. The magnitude of the biases tended to increase with the recombination rates when using 100 or more loci. On the other hand, the estimation of splitting times remained consistent as the number of loci increased. In the absence of recombination, the estimators of the IM model parameters remained consistent.

• 한국농공학회논문집
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• 제65권1호
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• pp.41-49
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• 2023

To utilize the hydraulic and hydrological models when simulating floods in agricultural watersheds, it is necessary to consider agricultural reservoirs, farmland, and farmland drainage system, which are characteristics of agricultural watersheds. However, most of them are developed individually by different researchers, also, each model has a different simulation scope, so it is hard to use them integrally. As a result, there is a need to link each hydraulic and hydrological model. Therefore, this study established an integrated flood simulation system for the comprehensive flood simulation of agricultural reservoir watersheds. The system can be applied easily to various watersheds because historical weather data and the SSP (Shared Socio-economic Pathways) climate change scenario database of ninety weather stations were built-in. Individual hydraulic and hydrological models were coded and coupled through Python. The system consists of multiplicative random cascade model, Clark unit hydrograph model, frequency analysis model, HEC-5 (Hydrologic Engineering Center-5), HEC-RAS (Hydrologic Engineering Center-River Analysis System), and farmland drainage simulation model. In the case of external models with limitations in conceptualization, such as HEC-5 and HEC-RAS, the python interpreter approaches the operating system and gives commands to run the models. All models except two are built based on the logical concept.

• 한국해양공학회지
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• 제35권2호
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• pp.121-130
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• 2021

In this study, a computational fluid dynamics (CFD) simulation based on an Eulerian-Eulerian approach was used to evaluate the mixing performance of a mud agitator through the distribution of bulk particles. Firstly, the commercial CFD software Star-CCM+ was verified by performing numerical simulations of single-phase water mixing problems in an agitator with various turbulence models, and the simulation results were compared with an experiment. The standard model was selected as an appropriate turbulence model, and a grid convergence test was performed. Then, a simulation of the liquid-solid multi-phase mixing in an agitator was simulated with different multi-phase interaction models, and lift and drag models were selected. In the case of the lift model, the results were not significantly affected, but Syamlal and O'Brien's drag model showed more reasonable results with respect to the experiment. Finally, with the properly determined simulation conditions, a multi-phase flow simulation of a mud agitator was performed to predict the mixing time and spatial distribution of solid particles. The applicability of the CFD multi-phase simulation for the practical design of a mud agitator was confirmed.