• 한국생산제조학회지
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• 제25권6호
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• pp.458-461
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• 2016

In this study, a finite element analysis for high-speed blanking of mild steel is performed. A thermomechanically coupled simulation model of a blanking process was developed using ABAQUS/Explicit. Through a simulation of the high-speed blanking process of mild steel, the influence of the punch speed, tool edge radius, and work material thickness on the development of the plastic heat and punch load were studied. The results of the study revealed that a higher punch speed caused thermal softening of the work material and decreased the punch load. Decreasing tool edge radius could help reduce the punch load. In addition, the results of the study revealed that the thermal softening effect was more dominant in the blanking of a mild steel sheet with a greater thickness as compared to that in the blanking of a mild steel sheet with a lower thickness.

• 대한기계학회논문집
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• 제13권1호
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• pp.125-134
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• 1989

본 연구에서는, 이러한 상황을 감안하여 피로시험을 위한 유사랜덤 (pseudorandom)하중 파형을 퍼스널컴퓨터 시뮬레이션에 의해 작성하는 소프트웨어를 개발함과 동시에 이를 이용하여 표면피로균열진전시험도 약간 수행하여, 변동하중하의 표면균열 진전거동에 관하여 대체적인 특성을 검토하여 보기로 하였다.

• Design & Manufacturing
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• 제2권2호
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• pp.43-47
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• 2008

This paper is concerned with the analysis of material flow characteristics of stepped rod forming. The analysis in this paper concentrated on the evaluation of the design parameters for deformation patterns of tube forming, load characteristics, extruded length, and die pressure. The design factors such as punch nose radius, die corner radius, friction factor, and punch face angle are involved in the simulation. The stepped rod forming is analyzed by using a commercial finite element code. This simulation makes use of stepped rod material and punch geometry on the basis of punch geometry recommended by International Cold Forging Group. As radius ratio is large, forming load was reduced but extruded length ratio was increased.

• 한국초전도ㆍ저온공학회논문지
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• 제15권1호
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• pp.19-24
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• 2013

In this paper, the Superconductor flywheel energy storage system (SFESS) was used for the load frequency control (LFC) of an interconnected 2 area power system. The robust SFESS controller using quantitative feedback theory (QFT) was designed to improve control performance in spite of parameter uncertainty and unexpected disturbances. An overlapping decomposition method was applied to simplify SFESS controller design for the interconnected 2 area power system. The model for simulation of the interconnected 2 area power system included the reheat steam turbine, governor, boiler dynamics and nonlinearity such as governor deadband and generation rate constraint (GRC). To verify robust performance of proposed SFESS controller, dynamic simulation was performed under various disturbances and parameters variation of power system. The results showed that the proposed SFESS controller was more robust than the conventional method.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.869-872
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• 2008

On this study, the Control of Temperature is specified on the view of indoor comfort and building energy consumption. It is estimated by Dynamic heat load simulation which has the factors of insulation method and the soil thickness of the green roof system. The fact that the model which has no insulation has the greatest effect of dropping high temperature and the cooling load decrease is confirmed.

• 한국시뮬레이션학회논문지
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• 제12권4호
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• pp.51-59
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• 2003

Real-Time applications on Grid environment have several problems in terms of resource management addressed as follows; (1) dynamic resource allocation to provide QoS objectives, (2) heterogeneous resources that is different scale, or capacity in same unit, and (3) resource availability, and resource needs. This paper describes the techniques of resource manager (RM) handling above problems to support QoS of dynamic real-time applications on Grid. The contributions of this paper to solve problems are as follows: unification of dynamic resource requirements among heterogeneous hosts, control of resources in heterogeneous environments, and dynamic load balancing/sharing. Our heuristic allocation scheme works not only 257% better than random, 142% better than round robin, and 36.4% better than least load in QoS sensitivity, but also 38.6% better than random, 28.5% better than round robin, and 31.6% better than least load in QoS.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2000년도 춘계학술대회 논문집
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• pp.1-6
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• 2000

현재 무인 운반 차량(AGV: Automated Guide Vehicle)은 자동화된 생산 및 저장 시스템에서 시스템간의 원활한 전달 및 회수를 위한 도구로 중요한 역할을 하고 있다. 하지만 시스템의 규모가 커짐에 따라 기존의 AGV 시스템의 운영 및 통제에 많은 어려움이 발생하게 되었고, 새로운 형태의 AGV 시스템의 설계를 통해 운영의 어려움을 해결하기 위한 연구들이 진행되고 있다. Tandem AGV 시스템, Divided AGV 시스템, SBSL(Segmented Bi-directional Single Loop) AGV 시스템 등이 대표적인 예이다. 이들 시스템들은 기존의 AGV 시스템과는 달리 전체 시스템을 몇 개의 지역으로 나누고, 각 지역에 한 대의 차량을 할당하는 방식으로 차량의 혼잡이나 충돌에 관한 운영의 어려움을 해결하려 하고 있다. 본 연구에서는 이러한 시스템들을 단일루프-단일차량형 AGV 시스템이라 정의하였다. 그리고 Multi-load AGV를 사용하는 단일루프-단일차량형 AGV 시스템을 설계하기 위한 방법론을 제시하고, 시뮬레이션을 통해 nit-load AGV를 사용하는 시스템과의 효율성을 비교, 분석하고자 한다.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.18-29
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• 2014

This paper proposes the integration of photovoltaic (PV) and energy storage systems for sustained power generation. In this proposed system, whenever the PV system cannot completely meet load demands, the super capacitor provides power to meet the remaining load. A power management strategy is designed for the proposed system to manage power flows between PV array systems and supercapacitors (SC). The main task of this study was to design PV systems with storage strategies including MPPT with direct control and an advanced DC-link controller and to analyze dynamic model proposed for a PV-SC hybrid power generation system. In this paper, the simulation models for the hybrid energy system are developed using Matlab/Simulink, SimPowerSystems and Matlab/Stateflow tool. This is the key innovative contribution of the research paper. The system performances are verified by carrying out simulation studies using practical load demand profile and real weather data.

• 전기학회논문지
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• 제58권10호
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• pp.2038-2040
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• 2009

This paper studies the state estimation problem for the current of DC/DC boost converters with parasitic inductor resistance. The parasitic resistance increases the system uncertainty when the output load variation occurs. In order to enhance the observation performance of the Luenberger observer this paper includes the integral of the estimation error signal to the estimation algorithm. By using the proposed PI observer the converter current signal is successfully reconstructed with the voltage measurement regardless of the load uncertainty. Computer simulation has been carried out by using Simulink/Sim Power System. Simulation results show the proposed method maintains robust estimation performance against the model uncertainty.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1235-1244
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• 2017

This paper proposes a fuzzy logic controlled new topology of high voltage gain zero voltage switching (ZVS) asymmetrical PWM full-bridge DC-DC boost converter for constant load and high power applications. The APWM full-bridge stage provides high voltage gain and soft-switching characteristics increase the efficiency and reduce the switching losses. Fuzzy logic controller (FLC) improves the performance and dynamic characteristics of the proposed converter. A comparison with a classical proportional-integral (PI) controller demonstrates the high performances of the proposed technique in terms of effective output voltage regulation under different operating conditions. Simulation is done by integrating two different simulation platforms $PSIM^{(R)}$ and $Matlab^{(R)}/Simulink^{(R)}$ by using SimCoupler tool of $PSIM^{(R)}$. Experimental results using 120W load have been provided to validate the results.