• Progress in Superconductivity
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• 제9권2호
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• pp.157-161
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• 2008

Due to high speed operations and ultra low power consumptions RSFQ logic circuit is a very good candidate for future electronic device. The focus of the RSFQ circuit development has been on the advancement of analog-to-digital converters and microprocessors. Recent works on RSFQ ALU development showed the successful operation of an 1-bit block of ALU at 40 GHz. Recently, the study of an RSFQ analog-to-digital converter has been extended to the development of a single chip RF digital receiver. Compared to the voltage logic circuits, RSFQ circuits operate based on the pulse logic. This naturally leads the circuit structure of RSFQ circuit to be pipelined. Delay time on each pipelined stage determines the ultimate operating speed of the circuit. In simulations, a two junction Josephson transmission line's delay time was about 10 ps, a splitter's 14.5 ps, a switch's 13 ps, a half adder's 67 ps. Optimization of the 4-bit ALU circuit has been made with delay time consideration to operate comfortably at 10 GHz or above.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3227-3233
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• 2009

본 논문에서는 나눗셈 행렬을 이용하여 부울 대입식을 산출하는 논리합성 방법을 제안한다. 최적화하고자하는 2개의 논리식들로부터 대수 나눗셈에 의한 행렬을 만들고 부울 공리와 리터럴 추가를 통해 부울 나눗셈 행렬로 확장을 한다. 부울 나눗셈 행렬에 리터럴을 추가하여 확장된 부울 나눗셈 행렬을 만들고, 원소들을 커버링하여 부울대입식을 산출한다. 실험결과 여러 벤치마크 회로에 대하여 제안한 방법이 기존 합성도구보다 리터럴 개수를 줄일 수 있음을 보였다.

• Earthquakes and Structures
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• 제11권2호
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• pp.347-369
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• 2016

The main objective of this paper is the robust multi-objective optimization design of semi-active tuned mass damper (STMD) system using genetic algorithms and fuzzy logic. For optimal design of this system, it is required that the uncertainties which may exist in the system be taken into account. This consideration is performed through the robust design optimization (RDO) procedure. To evaluate the optimal values of the design parameters, three non-commensurable objective functions namely: normalized values of the maximum displacement, velocity, and acceleration of each story level are considered to minimize simultaneously. For this purpose, a fast and elitist non-dominated sorting genetic algorithm (NSGA-II) approach is used to find a set of Pareto-optimal solutions. The torsional effects due to irregularities of the building and/or unsymmetrical placements of the dampers are taken into account through the 3-D modeling of the building. Finally, the comparison of the results shows that the probabilistic robust STMD system is capable of providing a reduction of about 52%, 42.5%, and 37.24% on the maximum displacement, velocity, and acceleration of the building top story, respectively.

• 대한전자공학회논문지
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• 제26권1호
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• pp.98-103
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• 1989

본 논문에서는 게이트 레벨에서 논리 최적화를 하기 위한, 새로운 시스템을 제안한다. 본 시스템은 회로의 일부분을 간략화된 등가회로로 대치하는 local transformation을 rule로 표현한 rule-based 시스템이다. 본 시스템에서는 효율적인 패턴매칭을 위해, 'rule의 일반화'와 '국소최적화'를 제안한다. Rule의 일반화는 패턴매칭시 회로탐색을 줄이기 위해 사용되며, 국소최적화는 불필요한 회로탐색을 배제하기 위해 사용된다. 또한, 불필요한 패턴매칭 시도를 줄이기 위해, 회로 패턴의 매칭순서를 rule 기술에 포함시킨다. 또한, 본 시스템을 하드웨어 컴파일러에 의해 생성된 논리회로 최적화에 적용하여, 그 효용성을 보인다.

• 한국멀티미디어학회논문지
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• 제25권8호
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• pp.1097-1108
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• 2022

This paper aimed to design and implement an EMS for real-time power generation control based on wake effect optimization of wind farm, and then to test it in commercial operating wind farm. For real-time control, we proposed the wake band-based optimization and setting the wake effect distance limit, and when the wake effect distance limit was set to 7D in the actual wind farm layout, the calculation time was improved by about 93.94%. In addition, we designed and implemented the script-based EMS for flexible operation logic management in preparation for unexpected issues during testing, and it was installed and tested on a wind farm in commercial operation. However, three issues arose during the testing process. These are the communication interface problem of meteorological tower, the problem of an abnormal wake effect, and the problem of wind turbine yaw control. These issues were solved by modifying the operation logic using EMS's script editor, and the test was successfully completed in the wind farm in commercial operation.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권2호
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• pp.128-133
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• 2010

This paper presents a method for estimating the parameters of dynamic models for induction motor dominating loads. Using particle swarm optimization, the method finds the adequate set of parameters that best fit the sampling data from the measurement for a period of time, minimizing the error of the outputs, active and reactive power demands and satisfying the steady-state error criterion.

• 대한전기학회논문지:전력기술부문A
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• 제48권2호
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• pp.145-152
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• 1999

This paper presents an optimal design method for fuzzy logic controllers using genetic algorithms. In general, the design of fuzzy logic controllers has difficulties in the acquisition of exper's knowledge and relies to a great extent on empirical and heuristic knowledge which, in many cases, cannot be objectively justified. So, the performance of the controller can be degraded in the case of plant parameter variations or unpredictable incident which the designer may have ignored, and parameters of the fuzzy logic controller obtained by expert's control action may not be global. To solve these problems, the proposed method using genetic algorithms in this paper, can tune the parameters of fuzzy logic controller including scaling factors and determine the appropriate number of fuzzy reles systematically and automatically. We provide the second drder dead time plant and inverted pendulum system to evaluate the feasibility and generality of our proposed method. Comparison shows that the proposed controller can producd higher accuracy and a smaller number of fuzzy rules than manually tuned fuzzy logic controller.

• 전자공학회논문지SC
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• 제47권1호
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• pp.29-34
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• 2010

본 논문에서는 새로운 패리티 보존형 가역 논리게이트를 제안한다. 패리티 보존형 가역 논리게이트는 입력 값과 출력 값의 패리티가 같은 가역 논리게이트를 의미한다. 최근 가역 논리 게이트가 저전력 CMOS 디자인, 양자 컴퓨팅 그리고 나노 테크놀로지와 같은 분야에서 전력을 효율적으로 사용하는 방법임을 알려졌다. 그리고 패리티 체크(parity-checking)는 디지털 시스템에서 오류 주입을 확인 하는 대표적인 방법 중 하나이다. 제안하는 새로운 패리티 보존형 가역 논리게이트는 모든 boolean 함수를 구성할 수 있고, 기존의 오류 확인 boolean 함수보다 가역 논리게이트 수, garbage-output의 수 그리고 하드웨어 연산량에서 효율적으로 구성할 수 있다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권2호
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• pp.173-180
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• 2012

This paper proposes a novel optimization algorithm inspired by water flowing and shaking behaviors in a vessel. Water drops in our algorithm flow to the gradient descent direction and are sometimes shaken for getting out of local optimum areas when most water drops fall in local optimum areas. These flowing and shaking operations allow our algorithm to quickly approach to the global optimum without staying in local optimum areas. We experimented our algorithm with four function optimization problems and compared its results with those of particle swarm optimization. Experimental results showed that our algorithm is superior to the particle swarm optimization algorithm in terms of the speed and success ratio of finding the global optimum.

• 한국지능시스템학회논문지
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• 제18권5호
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• pp.642-648
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• 2008

여자유도 매니퓰레이터의 동적 제어는 관절에 가해지는 토크를 최소화하는 목적으로 많은 연구가 이루어져 왔다. 그러나 기존의 국소 토크 최적화의 동적 제어 방법은 드라이버로 구현하기 힘든 토크가 요구된다. 본 논문에서는 그러한 큰 토크 요구를 상당히 개선시킨 새로운 제어 알고리즘을 제안한다. 이 알고리즘은 기존의 국소 토크 최소화 알고리즘에 퍼지 로직과 유전자 알고리즘을 적용시킨 것이다. 제안된 알고리즘은 3자유도 평면 여자유도 로봇에 적용하였으며, 시뮬레이션 결과를 통하여 제안된 알고리즘의 타당성을 확인하였다.