• 대한전자공학회논문지
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• 제23권4호
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• pp.557-564
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• 1986

This paper describes a standard cell placement strategy which consists of three kconsecutive steps` initial placement, iterative placement improvement, and string placement. In the initial placement step, cell placement was done by solving the linear ordering problem for a one-dimensional layout of standard cells and then zigzaging the resultant linear order width in the chip plane. The iterative placement improvement step is based on the iterative pairwise interchange using the estimated total routing length as a figure-or -merit. The string placement is used to reorder cells and terminals in each etandard cell row such that channel routing in the adjacent channels is not blocked by cyclic constraints and needs fewer routing tracks. The placement program is coded in PASCAL and kimplemented on a VAX-11/750 computer. Experimental results for several examples are included.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.254-257
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• 2004

Fiber placement system (FPS) carries out an advanced composites process which orients high strength reinforcing fibers in specific directions. The process includes wet winding, thermoset tape winding, thermoset prepreg placement and thermoplastic prepreg placement. FPS have the advantage of tape laying and filament winding with computer control and software. Using FPS can reduce costs, cycle times, structural weight, and handwork/rework when manufacturing composite parts. The sleeve extension is a part of the helicopter rotator systems. In this study, The sleeve extension composites were manufactured using FPS and tensile properties of this composites were characterized using universal testing machine(UTM).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.754-758
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• 1996

This paper presents a new approach to the design of self-tuning adaptive control system that is robust to the changing dynamic configuration as well as to the load variation factors using Digital signal processors for robot manipulators. TMS320C50 is used in implementing real-time adaptive control algorithms to provide advanced performance for robot manipulator, In this paper, an adaptive control scheme is proposed in order to design the pole-placement self-tuning controller which can reject the offset due to any load disturbance without a detailed description of robot dynamics. Parameters of discrete-time difference model are estimated by the recursive least-square identification algorithm, and controller parameters we determined by the pole-placement method. Performance of self-tuning adaptive controller is illusrated by the simulation and experiment for a SCARA robot.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.872-877
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• 1990

Robustness of a model refernece direct adaptive pole placement control for not necessarily minimum phase systems is studied subject to unmodeled dynamics and bounded disturbances. The adaptive control scheme involves two estimators for the system and the controller parameter estimation, respectively. The robustness is obtaind under some weak assumptions and by using both a normalized least-squares algorithm with dead zone and an appropriate nonlinear feedback.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.18-29
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• 2015

State Estimation (SE) is the basis of a variety of advanced applications used in most modern power systems. An SE problem formed with enough phasor measurement units (PMUs) data is simply a linear weighted least squares problem requiring no iterations. Thus, designing a minimum-cost placement of PMUs that guarantees observability of a power system becomes a worthy challenge. This paper proposes an equivalent integer linear programming method for substation-oriented optimal PMU placement (SOOPP). The proposed method uses an exhaustive search to determine a globally optimal solution representing the best PMU placement for that particular power system. To obtain a more comprehensive model, contingencies and the limitation of the number of PMU measurement channels are considered and embodied in the model as changes to the original constraints and as additional constraints. The proposed method is examined for applicability using the IEEE 14-bus, 118-bus and 300-bus test systems. The comparison between SOOPP results and results obtained by other methods reveals the excellence of SOOPP. Furthermore, practical large-scale power systems are also successfully analyzed using SOOPP.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.45-51
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• 2014

Distribution system is a critical link between customer and utility. The control of power loss is the main factor which decides the performance of the distribution system. There are two methods such as (i) distribution system reconfiguration and (ii) inclusion of capacitor banks, used for controlling the real power loss. Considering the improvement in voltage profile with the power loss reduction, later method produces better performance than former method. This paper presents an advanced evolutionary algorithm for capacitor inclusion for loss reduction. The conventional sensitivity analysis is used to find the optimal location for the capacitors. In order to achieve a better approximation for the current candidate solution, Opposition based Differential Evolution (ODE) is introduced. The effectiveness of the proposed technique is validated through 10, 33, 34 and85-bus radial distribution systems.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.150-155
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• 1996

This paper presents a new approach to the design of self-tuning adaptive control system that is robust to the changing dynamic configuration as well as to the load variation factors using digital signal processors for robot manipulators. TMS3200C50 is used in implementing real-time adaptive control algorithms provide advanced performance for robot manipulator. In this paper an adaptive control scheme is proposed in order to design the pole-placement self-tuning controller which can reject the offset due to any load disturbance without a detailed description of robot dynamics. parameters of discrete-time difference model are estimated by the recursive least-square identification algorithm and controller parameters are detemined by the pole-placement method. Performance of self-tuning adaptive controller is illusrated by the simulation and experiment for a SCARA robot.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.61-64
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• 1996

This paper presents a new approach to the design of self-tuning adaptive control system that is robust to the changing dynamic configuration as well as to the load variation factors using Digital signal processors for robot manipulators. TMS32OC50 is used in implementing real-time adaptive control algorithms to provide advanced performance for robot manipulator. In this paper, an adaptive control scheme is proposed in order to design the pole-placement self-tuning controller which can reject the offset due to any load disturbance without a detailed description of robot dynamics. Parameters of discrete-time difference model are estimated by the recursive least-square identification algorithm, and controller parameters are determined by the pole-placement method. Performance of self-tuning adaptive controller is illustrated by the simulation and experiment for a SCARA robot.

• 한국지반신소재학회논문집
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• 제4권3호
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• pp.45-52
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• 2005

대부분의 항만구조물은 초연약 지반상에 축조되고 있으며 도로나 건물부지에는 지반개량이 필요하다. 이 논문에서는 여러 사례연구를 통하여 표층처리후의 복토사례에 대하여 몇가지 고려사항을 언급하였다. 또한, 모래나 산토를 이용한 복토공법에 대하여 강도적용이 고려되었다. 국내 복토공법 토목섬유 인장강도는 15t/m, 복토두께는 1.6~3.1m, 점토지반의 표층강도는 $0.2{\sim}1.2t/m^2$이 대표적이다. 표층처리공 시공시 발생되는 지반교란, 점토유출, 장비전도 등의 사고를 최소화하기 위한 연구가 필요하다.

• 영재교육연구
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• 제24권6호
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• pp.1001-1024
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• 2014

본 연구에서는 과학영재학교에서 AP(Advanced Placement)를 경험하고 현재 대학생이 된 39명의 영재고 졸업생들과의 심층인터뷰를 통해 영재학교에서 운영 중인 AP의 운영실제 및 그 의미를 탐색하고 2015년부터 과학고로의 전면적 확대를 앞두고 있는 AP의 향후 방향성을 모색해보고자 하였다. 현재 영재학교 학생들은 기초필수와 선택과목 등으로 평균 8과목 이상의 AP 과목을 수강하고 있었다. AP 교과목의 경우, 대개는 영재학교 2학년부터 수강이 이루어지는 것이 일반적이나 PT(placement test)를 통해 1학년 때부터 AP과목을 수강하는 경우도 있었다. AP로 제공되는 선택과목들은 전공별로 차이가 있어 수학 교과에서는 비교적 많은 전공 선택 과목이 제공되고 있으나 생물이나 전산 교과등을 이수하려는 학생들에게는 상대적으로 선택의 폭이 적었다. 본 연구에 참여한 학생들에 의하면 영재학교에서의 AP는 오히려 대학에서의 수업보다 내용상 더 어려웠으며 소수인원으로 진행되는 만큼 활발한 교사-학생 상호작용과 함께 충실하게 운영되었다. 하지만 AP 과목의 이수 인정 학점인 C+의 타당성과 관련해서는 상이한 의견이 제시되었다. 연구결과 학생들은 AP로 단축된 시간을 다양한 측면으로 활용하고 있었다. AP가 0.5년에서 1.5년의 조기졸업을 위한 통로로도 활용되어지지만, 학생들은 AP로 단축된 시간을 복수전공, 부전공, 해외 교환학생 등과 같이 다양한 기회로 활용하고 있음을 알 수 있었다. 특히 남학생들의 경우 AP로 인해 단축된 시간이 있어 군복무 기간에 대해 다소 부담감을 덜 느끼는 것을 알 수 있었고, AP가 학생 개개인 관심사나 연구를 위한 시간적 여유를 제공해주기도 하였으며, 무엇보다 AP를 통해 고등학교에서 보다 진지하게 진로를 탐색하고 경험할 수 있는 유용한 시간이었다고 학생들은 지적한다. 본 연구는 과학영재학교와 과학고등학교에서 AP 과정이 성공적으로 정착하고 더욱 확대 발전하기 위해서 학교-대학 간의 보다 원활한 행정시스템 개선, AP 과목 인정 대학의 확대 등을 포함한 몇 가지 현실적 제언을 제시하고 있다.