• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.805-812
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• 2006

An optimization formulation is proposed to minimize sound pressures in a two-dimensional cavity by controlling the attachment area of unconstrained damping materials. For the analysis of structural-acoustic systems, a hybrid approach that uses finite elements for structures and boundary elements for cavity is adopted. Four-parameter fractional derivative model is used to accurately represent dynamic characteristics oJ the viscoelastic materials with frequency and temperature. Optimal layouts of the unconstrained damping layer on structural wall of cavity are identified according to temperatures and the amount of damping material by using a numerical search algorithm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.980-986
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• 2007

본 연구는 매우 짧은 차간 간격을 요구하면서 차량 간의 충돌을 피하기 위해서 매우 정확한 속도제어를 필요로 하는 개인 고속 이동 시스템의 운행제어 알고리즘의 검증을 위한 검증 시스템의 설계에 대해서 다룬다. 검증시스템은 모의 차량, 중앙제어 시스템, 모의지상설비, 모니터링 장치로 구성된다. 모의차량은 총 4EA의 서버(노트북)로 구성 하며, 중앙(지역)제어시스템은 산업용 Motorola사(社)의 PowerPC기반 프로세서 모듈 및 I/O 보드 장치로 구성한다. 모의지상설비는 National Instruments社의 PXI 산업용 제어기를 사용하여 구현한다. 설계된 검증시스템의 시험을 위해서 Labview Simulation Interface Toolkit 과 Matlab/Simulink 가 결합된 환경하에서 모의시험을 거친 시험용 알고리즘을 이용한다.

• 소음진동
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• 제8권4호
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• pp.683-689
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• 1998

A control algorithm for multi-stage dampers is developed based on the mode skyhook control concept, and implemented on the full vehicle system environment. The test vehicle system is equipped with the real time controller, four-stage variable dampers and sensors. The real time controller is developed using a digital signal processor(DSP), digital I/O, A/D and D/A converters. The dampers are driven by the electromagnetic actuators of less than 20 msec response time. The sensors include accelerometers, relative displacement transducers, and steering wheel rate sensors, etc. Through a series of tests in laboratory and proving ground, the performance of the semi-active suspension system is evaluated and it is shown that the vehicle dynamic characteristics is improved with the developed damping system. Futhermore, the parameter tuning methods to enhance vehicle dynamic performance are propsoed.

• 전자공학회논문지A
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• 제31A권2호
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• pp.116-124
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• 1994

This paper describes the design of a high-level synthesis system. ISyn: Interface Synthesis System for ISPS-A. which generates hardware satisfying timing constraints. The original version of ISPS is extended to be used for the description/capture of interface operations and timing constraints in the ISPS-A. To generate the schedule satisfying interface constraints the scheduling process is divided into two steps:pre-scheduling and post-scheduling. ISyn allocates hardware modules with I/O ports by the clique partitioning algorithm. Experimental results show that ISyn is capable of synthesizing hardware modules effectively for internal and/or interactive operations.

• 전자공학회논문지C
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• 제34C권8호
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• pp.8-21
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• 1997

In this paper, we consider resistive shorts on gate-source, gate-drain, and drain-source as well as opens in MOS FETs included in typical memory cell of VLSI SRAM and analyze behavior of memory by using PSPICE simulation. Using conventional fault models and this behavioral analysis, we propose linear testing algorithm of complexity O(N) which can be applied to both functional testing and IDDQ (quiescent power supply current) testing simultaneously to improve functionality and reliability of memory. Finally, we implement BIST (built-in self tsst) circuit and BICS(built-in current sensor), which are embedded on memory chip, to carry out functional testing efficiently and to detect various defects at high-speed respectively.

• 대한전자공학회논문지
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• 제20권3호
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• pp.45-51
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• 1983

본 논문에서는 대규모 시스템을 위한 준최적 저감도성 비집중형 제어기를 설계하기 위하여 준최적 이득 행렬을 구하기 위한 필요조건과 알고리즘을 유도하였다. 또한 감도를 고려하지 않은 종래의 비집중제어기와의 비교를 위하여 수치적 예를 들어 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.498-499
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• 2008

신재생에너지의 개발, 정부의 규제 완화와 환경적 이유로 인해 배전계통에서 분산전원은 점차 증가하는 추세이다. 최근 분산전원을 소유한 구역전기사업자가 전력시장의 새로운 시장 참여자로서 대두되고 있다. 분산전원을 소유한 구역전기사업자는 최대 이윤을 얻기 위해서 매 시간마다 발전량을 변화시켜야 한다. 본 논문에서는 배전계통에 연계된 분산전원의 최적 운영에 대해서 소개할 것이다. 이 때, 최적화의 목적은 구역전기사업자 이윤의 최대화이며, 국제적 환경규제에 따른 온실가스배출량을 고려하여 발전비용을 산출한다. 산출기법으로 Particle Swarm Optimization 알고리즘을 이용한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1142-1143
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• 2008

As well known, the maximum power point tracking (MPPT) is an important role in photovoltaic (PV) power systems. MPPT finds and maintains the operation of PV at the maximum power point when the irradiation and cell-temperature change. In this paper, the studied system includes a PV array, a Buck-Boost DC/DC converter, a DC/AC inverter and it is connected to the three phase power system. The solar array operates as a non-linear voltage source. The P&O algorithm with power feed-back is used to control the operating point of PV array at the maximum power point. The effects of irradiation and cell-temperature on the dynamic responses are also considered.

• Structural Engineering and Mechanics
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• 제64권5호
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• pp.579-589
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• 2017

This paper deals with the optimum cost design of partially prestressed concrete I crosssectioned beams by using Genetic Algorithms. For this purpose, the optimum cost design of two selected example problems that have different characteristics in behavior are performed via Genetic Algorithms by determining their objective functions, design variables and constraints. The results obtained from the technical literature are compared with the ones obtained from this study. The interpretation of the results show that the design of partially prestressed concrete I crossectioned beams from cost point of view by using Genetic Algorithms is 35~50 % more economical than the traditional ones (technical literature) without conceding safety.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 추계 학술대회논문집
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• pp.42-47
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• 1999

In this study, we adopt the point symmetric Gauss-Seidel relaxation algorithm to obtain the steady state solution of the Navier-Stokes equations for the thermal and chemical nonequilibrium flow of air. All of the inviscid, viscous flux Jacobians and thermochemical source Jacobians are included in the implicit part Numerical simulation is performed for the thermal and chemical nonequilibrium flow over blunt body and computational results are presented. The convergence history and CPU time of the present computation are compared with the LU-SGS scheme which employs the approximate Jacobians.