• Journal of Advanced Marine Engineering and Technology
• /
• 제28권2호
• /
• pp.200-209
• /
• 2004

The fuzzy control based on $\alpha$-level fuzzy set decomposition. It is known to produce quick response and calculating time of fuzzy inference. This paper derived the embodiment computational algorithm for defuzzification by min-max fuzzy inference and the center of gravity method based on $\alpha$-level fuzzy set decomposition. It is easy to realize the fuzzy controller hardware. based on the calculation formula. In addition. this study proposed a circuit that generates PWM actual signals ranging from fuzzy inference to defuzzification. The fuzzy controller was implemented with mixed analog-digital logic circuit using the computational fuzzy inference algorithm by min-min-max and defuzzification by the center of gravity method. This study confirmed that the fuzzy controller worked satisfactorily when it was applied to the position control of a dc servo system.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 전력전자학술대회 논문집
• /
• pp.662-665
• /
• 2001

As the fuzzy control is applied to servo system the hardware implementation of the fuzzy information systems requires the high speed operations, short real time control and the small size systems. The aims of this study is to develop hardware of the fuzzy information systems to be apply to servo system. In this paper, we propose a calculation method of approximate reasoning for fuzzy control based on $\alpha$-level set decomposition of fuzzy sets by quantize $\alpha$-cuts. This method can be easily implemented with analog hardware. The influence of quantization levels of $\alpha$-cuts on output from fuzzy inference engine is investigated. It is concluded that 4 quantization levels give sufficient result for fuzzy control performance of do servo system. It examined useful with experiment for dc servo system.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제54권2호
• /
• pp.90-96
• /
• 2005

This paper presents hardware scheme of fuzzy inference engine, based on α-level set decomposition of fuzzy sets for fuzzy control of DC servo system. We propose a method which is directly converted to PWM actuating signal by a one body of fuzzy inference and defuzzification. The influence of quantity α-levels on input/output characteristics of fuzzy controller and output response of DC servo system is investigated. It is concluded that quantity α-cut 4 give a sufficient result for fuzzy control performance of DC servo system. The experimental results shows that the proposed hardware method is effective for practical applications of DC servo system.

• 융합신호처리학회논문지
• /
• 제2권3호
• /
• pp.50-56
• /
• 2001

퍼지제어가 서보시스템에 응용할 때 퍼지정보 시스템의 하드웨어 실현은 고속연산, 짧은 실시간의 제어 및 시스템의 소형 경량화가 요구되고 있다. 본 연구의 목적은 서보시스템에 적용하기 위한 퍼지정보 시스템의 하드웨어를 개발하는 것이다. 본 연구에서는 $\alpha$-레벨 집합의 분해 원리에 기초하여 $\alpha$-컷 양자화에 따라 퍼지추론의 계산 방법을 제안하려다. 이 방법은 퍼지제어기의 아날로그 하드웨어의 구성을 쉽게 행할 수 있다. $\alpha$-컷 양자화에 따른 회지추론 엔진의 출력으로 $\alpha$-컷 양자화에 따른 퍼지추론 영향을 조사하였고 $\alpha$-컷 양자화 4 단계에서 DC 서보시스템의 퍼지제어에 양호한 결과를 얻었다. 제안한 퍼지추론 연산과 중심법에 의한 비퍼지화에서 직접 PWM 조작 신호를 얻는 방법을 나타내었다. 서보계의 실험을 행하여 유용성을 구명하였다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제28권5호
• /
• pp.793-800
• /
• 2004

The purpose of this study is to develope a servo system with faster and more accurate response. This paper describes a method of approximate reasoning for fuzzy control of servo system based on the decomposition of $\alpha$-level fuzzy sets. We propose that fuzzy logic algorithm is a body from fuzzy inference to defuzzificaion cases where the output variable u directly is generated PWM The effectiveness for robust and faster response of the fuzzy control scheme are verified for a variable parameter by comparison with a PID control and fuzzy control A position control of DC servo system with a fuzzy logic controller is demonstrated successfully.

• Communications for Statistical Applications and Methods
• /
• 제17권4호
• /
• pp.611-624
• /
• 2010

Several methods were suggested for constructing a fuzzy relationship between fuzzy independent and dependent variables. This paper reviews the use of the method by minimizing the square of the difference between an observed and a predicted fuzzy number in an ${\alpha}$-level linear regression model. We introduce a new distance between fuzzy numbers on the basis of a mode, a core point and a radius of an ${\alpha}$-level set of a fuzzy number an construct the fuzzy regression model using the proposed fuzzy distance. We also investigate sufficient condition for an equivalence in the ${\alpha}$-level regression model.

• 한국정보통신학회논문지
• /
• 제8권5호
• /
• pp.1050-1057
• /
• 2004

연구의 목적은 컴퓨터 도움 없이 독립으로 서보시스템의 퍼지제어를 위한 퍼지제어기 하드웨어 회로 개발이다 본 논문은 $\alpha$-레벨 퍼지집합 분해에 기초하여 DC 서보 시스템의 퍼지제어를 위해 퍼지 추론 연산의 하드웨어에 대하여 나타내었다. 퍼지추론에서 비퍼지화까지 일체적으로 퍼지추론 연산에 의해 직접 PWM 조작신호를 얻는 방법이 제안되었다. 이 방법은 아날로그 회로로 쉽게 구현할 수있다. 퍼지제어기 입출력 특성과 직류서보 전동기 퍼지제어 응답특성에서 $\alpha$-레벨 양자화 효과에 대하여 검토한 결과 양자화 수 $\alpha$=4 단계가 충분한 것을 알 수 있다. 제안한 하드웨어 방법은 실 직류 서보시스템의 적용에서 실험을 통하여 그 효과를 나타내었다.

• Communications for Statistical Applications and Methods
• /
• 제16권5호
• /
• pp.781-790
• /
• 2009

본 논문에서는 퍼지수를 포함한 모수적 회귀모형을 추정하기 위하여 분포무관추정량으로 알려진 순위 변환방법과 Theil 방법을 소개한다. 순위 변환방법은 퍼지수의 ${\alpha}$-수준집합의 중심과 폭에 대한 순위를 이용하고 Theil 방법은 ${\alpha}$-수준집합의 중심과 폭에 대한 추정한 값들의 중위수를 이용한다. 예제를 이용하여 분포무관추정량으로 추정된 퍼지회귀모형의 효율성을 최소자승법과 여러 가지 방법으로 추정된 퍼지회귀모형과 비교한다.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2001년도 추계학술대회 학술발표 논문집
• /
• pp.353-356
• /
• 2001

In this paper, we study the existence of fuzzy solution for the following differential system with fuzzy coefficient using the different two methods: (equation omitted), where a, b is the fuzzy natural number generated by fuzzy number l . The a-level set of the fuzzy number (equation omitted). The -level set of a is (equation omitted) and -level set of b is (equation omitted).

• 대한화학회지
• /
• 제57권6호
• /
• pp.684-690
• /
• 2013

Since a glycerol molecule has three active sites, two ${\alpha}$ and one ${\beta}$ hydroxyl groups; it undergoes condensation by releasing water molecules to produce linear, nonlinear and heterocyclic oligomers. The Gibbs free energy (G), enthalpy (H) and internal energy (E) of 7 diglycerol, 15 triglycerol and 23 tetraglycerol isomers were calculated at B3LYP level of theory using 6-311++G(d, p) basis set, in both gas and aqueous phases. Linear oligomers, ${\alpha}{\alpha}$-diglycerol, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-triglycerol and ${\alpha}{\alpha}$, ${\alpha}{\alpha}$, ${\alpha}{\alpha}$-tetraglycerol, were found to be the most stable oligomers in aqueous phase. It was found that the stability of cyclic oligomers decreases as the size of their rings increases. Cyclic oligomers are produced by dehydration of the acyclic ones which is an endothermic reaction while its ${\Delta}G$ is negative. The dehydration reaction is less endothermic in aqueous phase.