• 정보과학회 논문지
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• 제42권12호
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• pp.1503-1521
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• 2015

에이전트 기반 모델링 및 시뮬레이션(Agent-Based Modeling and Simulation)은 기존 시스템 수준에서의 시뮬레이션이 구현할 수 없는 에이전트의 세밀한 행동과 상호작용을 활용하여 시장이나 사회 현상의 모델링에 사용되는 기술이다. 그러나 에이전트 기반 모델링 및 시뮬레이션은 에이전트 기반 시스템의 지식 수준에서의 합리성의 원칙에 기반하여 구현되기 때문에 스스로의 목표 달성을 저해하는 에이전트를 표현할 수 없다[1]. 에이전트 기반 소프트웨어 공학 분야에서는 이러한 한계를 극복하기 위해 사회적 수준에서의 행동 법칙을 통해 해결하였으나[2], 구체적인 개발 방법론은 제시가 되어 있지 않다. 따라서 본 연구에서는 에이전트 기반 소프트웨어 공학 방법론인 트로포스와 사회적 행동 법칙을 결합하여 사회적 행동 법칙을 반영한 새로운 에이전트 기반 모델링 및 시뮬레이션 방법을 제안한다. 이를 위해 각 개발 단계별로 구체적인 과업을 명시하고 과업 별로 생성되는 산출물 분석을 통해 모델링 및 시뮬레이션의 과정을 설명한다. 또한 자가 적응적 스마트 그리드와 군 도메인 시스템에서의 구체적인 적용 사례와 실험을 통해 제안 방법을 검증한다.

• 설비공학논문집
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• 제17권2호
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• pp.147-155
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• 2005

For a long road tunnel, a tunnel ventilation system may be used in order to reduce the pollution level below the required level. To control the tunnel pollution level, a closed loop control algorithm may be used. The cascade control algorithm, which composed of a jet fan control algorithm and an air velocity setpoint algorithm, was developed to regulate the CO level in a tunnel. The verification of control algorithms was carried out by dynamic models developed from real tunnel data sets. The simulation results showed that control algorithms developed for this study were effective to control the tunnel ventilation system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.95-98
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• 2006

This paper proposes high speed SRM drive system for blower with a new 4-level inverter and precise excitation position generator. For the high speed blower, a proper inverter and control method are proposed and the output characteristics are analyzed. In order to get a fast build-up and demagnetization of excitation a current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build-up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulation and experimental result.

• Journal of Power Electronics
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• 제1권1호
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• pp.26-35
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• 2001

In most inverter/converter applications SVPWM method is a preferred approach since it shows good characteristics in linear modulation range and waveform quality. In this paper, we propose a new carrier based SVPWM method for multi-level system, First, we survey the conventional carrier based SVPWM method, and investigate the problem of the conventional one for the multi-level system with the focus on the switching frequency harmonic flux trajectories. Finally, we propose a new carrier based SVPWM method that can reduce harmonic distortion. Simulation and experimental results are given for verification of the proposed SVPWM method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.658-663
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• 1987

The new controller developed here, which is the facility with only one measurement, is a new concept for the level controller of the existing nuclear steam generator. A MACS (Microcomputer-based Adaptive Control System of a Steam Generator) is quite practical and efficient, and has also simple structure and higher flexibility in the installment for actual plant. A key ingredient of this system is adaptive regulator which can calculate adaptive, optimal valve position in response to changes in the dynamics of the process and the disturbances. In spite of many difficulties in the steam generator water level control at low power, it can be concluded from the experimental and simulation results, that the MACS can provide optimal, robust steam generator level control from zero to full power. The amount of the control input effort can be reduced by adjusting the weighting factor. However, the steady state water level errors are generated. To avoid the steady errors, the different adaptive algorithm should be investigated in the future. The 3 second sampling time is acceptable for this system. However, action should be taken to shorten the sampling time for better digital control.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.326-332
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• 2018

In this paper, the design process and the control method of the power conversion system (PCS) that consists of a bidirectional DC-DC converter and a 3-level T-type inverter for an energy storage system is presented. Especially the design method of the output LCL filter for a 3-lvel T-type inverter without complex mathematical process are proposed. The validity of the control method and design process in this paper are verified through simulation and experimental analysis.

• 한국시뮬레이션학회논문지
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• 제26권2호
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• pp.9-17
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• 2017

현대사회의 다양한 분야에서는 복잡한 사회현상에 대하여 문제를 정의하고 문제해결책의 결과를 분석하는 과정으로 모델링 및 시뮬레이션을 활용하고 있다. 나날이 사회현상의 문제가 복잡해짐에 따라 요구되는 모델링 및 시뮬레이션 환경의 계산자원의 요구사항도 높아지고 있다. 이러한 요구사항을 수용하기 위해서 클라우드 서비스 등과 같이 컴퓨팅 자원을 유동적으로 사용할 수 있는 환경이 대두되었다. 본 연구에서는 이러한 컴퓨팅 자원 활용 시스템을 보다 효율적으로 활용할 수 있는 웹 기반 재구성이 가능한 시뮬레이션 실험 틀을 제안한다. 제안하는 시뮬레이션 실험 틀은 다양한 분산 컴퓨팅 환경을 지원할 수 있도록 프론트엔드(Front-end)에서 웹을 활용하여 시뮬레이션 모델의 재구성 시스템을 구축하고 백엔드(Back-end) 이산 사건 시뮬레이션의 실행을 담당하는 이산사건 시뮬레이션 실행단으로 구성된다. 본 연구는 사례연구를 통해 분산형 시뮬레이션 환경이 단일 시뮬레이션 환경보다 시간적 효율이 더 높음을 확인하였다.

• 한국시뮬레이션학회논문지
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• 제3권2호
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• pp.27-36
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• 1994

In many real-world simulation studies the several measures of performance are of interest simultaneously. There exist very limited number of studies that explain and suggest the methods or procedures of inferencing the system performances at the same time. This study presents a procedure for determining the number of simulation observations required to achieve the prespecified confidence level for several measures of system performance. Mean values are selected as the measures, for instance, expected ordering cost, expected holding cost, and expected shortage cost for a given period of time in the study of inventory problems. Basically, the batch means approach is applied and extended to develop an algorithm to carry out the procedure handling more than single parameter. The efficacy of the presented method is assessed through the experiments. The empirical results based on some stochastic systems such as queues and inventory problems show that the suggested method produces as excellent result in terms of the precision of estimated means and the number of observations required.

• 산업공학
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• 제8권3호
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• pp.61-73
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• 1995

As the level of maunfacturing system automation increases, the issues of modeling and simulation of AMS(Automated Manufacturing System) are becoming more important. Proposed in this paper is the JR-Net(Job Resource relation-Net) modeling framework which naturally mimics the process of designing an AMS by FA(Factory Automation) engineers. Its main purpose is to provide a modeling tool which facilitate modeling work of AMS for FA engineers unfamiliar with simulation modeling. The proposed modeling scheme is based on the extensive observation that typical AMSs are built from the set of 'standard' components(or catalog items). As an application of the proposed model, two real examples of FMS('G7'FMS model plant, RPI FMS) are modeled by JR-Net, and in case of FMS model plant, a simulation program development procedure using JR-Net modeling results is explained. Finally, simulation result of FMS model plant is analyzed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.513-520
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• 2004

A steady-state/transient performance simulation model was newly developed for the propulsion system of the CRW (Canard Rotor Wing) type UAV (Unmanned Aerial Vehicle) during flight mode transition. The CRW type UAV has a new concept RPV (Remotely Piloted Vehicle) which can fly at two flight modes such as the take-off/landing and low speed forward flight mode using the rotary wing driven by engine bypass exhaust gas and the high speed forward flight mode using the stopped wing and main engine thrust. The propulsion system of the CRW type UAV consists of the main engine system and the duct system. The flight vehicle may generally select a proper type and specific engine with acceptable thrust level to meet the flight mission in the propulsion system design phase. In this study, a turbojet engine with one spool was selected by decision of the vehicle system designer, and the duct system is composed of main duct, rotor duct, master valve, rotor tip-jet nozzles, and variable area main nozzle. In order to establish the safe flight mode transition region of the propulsion system, steady-state and transient performance simulation should be needed. Using this simulation model, the optimal fuel flow schedules were obtained to keep the proper surge margin and the turbine inlet temperature limitation through steady-state and transient performance estimation. Furthermore, these analysis results will be used to the control optimization of the propulsion system, later. In the transient performance model, ICV (Inter-Component Volume) model was used. The performance analysis using the developed models was performed at various flight conditions and fuel flow schedules, and these results could set the safe flight mode transition region to satisfy the turbine inlet temperature overshoot limitation as well as the compressor surge margin. Because the engine performance simulation results without the duct system were well agreed with the engine manufacturer's data and the analysis results using a commercial program, it was confirmed that the validity of the proposed performance model was verified. However, the propulsion system performance model including the duct system will be compared with experimental measuring data, later.