• 한국지능시스템학회논문지
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• 제7권2호
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• pp.3-15
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• 1997

퍼지논리를 적용하기 위해서는 두가지 과제가 이루어져야 하는데 그것은 퍼지룰의 유도와 맴버쉽함수의 결정이다. 이 과제는 어렵고 또한 시간을 요하게 된다. 본 논문에서는 문제에 적용 가능한 멤버쉽함수와 퍼지룰을 자동으로 유도하기 위한 알고리즘적 방법을 제시하고 있다. 이 알고리즘적 방법은 샘플을 구분하는 엔트로피 최소화의 원리에 입각하고 있다. 멤버쉽함수는 샘플을 연속적으로 구분하여 이루어지며 퍼지룰 또한 엔트로피 최소화 원리에 의하여 이루어진다. 퍼지룰의 유도에서는 룰 비중 또한 같이 계산된다. 결정 문제에 적용을 위한 추론법 및 방법도 논의되었다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.884-888
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• 2003

In this paper, we introduce the hybrid data mining mechanism based in association rule and fuzzy neural networks (FNN). Most of data mining mechanisms are depended in the association rule extraction algorithm. However, the basic association rule-based data mining has not the learning ability. In addition, sequential patterns of association rules could not represent the complicate fuzzy logic. To resolve these problems, we suggest the hybrid mechanism using association rule-based data mining, and fuzzy neural networks. Our hybrid data mining mechanism was consisted of four phases. First, we used general association rule mining mechanism to develop the initial rule-base. Then, in the second phase, we used the fuzzy neural networks to learn the past historical patterns embedded in the database. Third, fuzzy rule extraction algorithm was used to extract the implicit knowledge from the FNN. Fourth, we combine the association knowledge base and fuzzy rules. Our proposed hybrid data mining mechanism can reflect both association rule-based logical inference and complicate fuzzy logic.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 심포지엄 논문집 정보 및 제어부문
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• pp.155-156
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• 2008

In this paper, an interval type-2 fuzzy logic system is designed and compared with a type-1 fuzzy logic system. To compare performance of a type-1 fuzzy logic system with the type-2 fuzzy logic system, we apply type-1 fuzzy logic system and type-2 system to modeling the noised data. Membership function of interval type-2 fuzzy logic system is designed consequents of rules including uncertainty. For general type-2 fuzzy logic system computational complexity is severe. On the other hand, theoretic and arithmetic computations for interval type-2 fuzzy logic systems are very simple.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.579-583
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• 1991

A fuzzy logic controller with rule modification capability is proposed to overcome the difficulty of obtaining control rules from the human operators. This new SOC algorithm modifies control rules by a fuzzy inference machine utilizing data base. Computer simulation results show good performances on both a linear system and a nonlinear system.

• International Journal of Control, Automation, and Systems
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• 제4권2호
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• pp.155-164
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• 2006

This paper focuses on a new optimization technique of a fuzzy logic based proportional integral (FLPI) load frequency controller by the multiple tabu search (MTS) algorithm. Conventionally, the membership functions and control rules of fuzzy logic control are obtained by trial and error method or experiences of designers. To overcome this problem, the MTS algorithm is proposed to simultaneously tune proportional integral gains, the membership functions and control rules of a FLPI load frequency controller in order to minimize the frequency deviations of the interconnected power system against load disturbances. The MTS algorithm introduces additional techniques for improvement of the search process such as initialization, adaptive search, multiple searches, crossover and restart process. Simulation results explicitly show that the performance of the proposed FLPI controller is superior to conventional PI and FLPI controllers in terms of overshoot and settling time. Furthermore, the robustness of the proposed FLPI controller under variation of system parameters and load change are higher than that of conventional PI and FLPI controllers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.389-394
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• 2004

A Fuzzy Logic Sliding Mode Control or FLSMC for the uninterruptible power system (UPS) is presented, which is tracking a sinusoidal ac voltage with specified frequency and amplitude. The FLSMC algorithm combines feedforward strategy with the Variable Structure Control (VSC) or Sliding Mode Control (SMC) and fuzzy logic control. The control function is derived to guarantee the existence of a sliding mode. FLSMC has an advantage that the stability of FLSMC can be proved easily in terms of VSC. Furthermore, the rules of the proposed FLSMC are independent of the number of system state variables because the input of the suggested controller is fuzzy quantity sliding surface value. Hence the rules of the proposed FLSMC can be reduced. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances. It has the small overshoot in the transient and the smaller chattering in the steady state than the conventional VSC. Moreover, its can achieve the requirements of robustness and can supply a high-quality voltage power source in the presence of plant parameter variations, external load disturbances and nonlinear dynamic interactions.

• Journal of Biosystems Engineering
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• 제23권4호
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• pp.365-372
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• 1998

This study was carried out to develop a nutrient-solution mixing-and-supplying system, which used a low-cost metering device instead of expensive metering pumps and a fuzzy logic controller. A low cost and precise overflow-type metering device was developed and evaluated by testing the flow discharge for the automatic nutrient-solution mixing-and-supplying system for snail-scale hydroponic sewers. The fuzzy logic controllers, which could predict and meet the desired values of EC and supply rate of nutrient solution were developed and verified by simulation and experiment. this fuzzy logic controller, whose algorithm consists of four crisp inputs, two crisp outputs and nine rules, was developed to predict the desired value of EC and supply rate of nutrient solution and two crisp inputs, one crisp output and nine rules used to control EC to the desired values. The nutrient-solution mixing-and-supplying system showed satisfactory EC control performance with the maximum overshooting of 0.035 mS/cm and the maximum settling time of 15 minutes in case of increasing 0.7 mS/cm. also, the accuracy of the overflow-type metering device in terms of the full-scale error was 2.29% when using solenoid valve only and 0.2% when using solenoid valve and flow control valve together.

• 전기전자학회논문지
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• 제22권2호
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• pp.440-445
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• 2018

본 논문은 미지 유동환경에서 다중 이동로봇들의 주행문제에 대한 연구결과이다. 여기에서 환경은 로봇에게는 알려져 있지 않기 때문에 로봇의 몸체에 부착된 근접센서들을 이용하여 주변환경들을 감지하여야 하고, 로봇이 충돌 없이 경로를 추적하여 목표지점에 도착하도록 기본 방책들을 조합한 지능주행 방법을 제안하였다. 이러한 대부분 기법들은 퍼지논리 제어기들을 이용하여 구현하였으며, 모든 로봇에 동일하게 적용하였다. 퍼지 제어기의 성능을 향상시키기 위해서 유전 알고리즘을 이용하여 퍼지 제어기의 membership function과 rules set를 진화시켰다. 모의실험 결과 제안한 방법이 주행문제에 긍정적인 결과가 있음이 증명되었다.

• 한국지능시스템학회논문지
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• 제16권3호
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• pp.303-308
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• 2006

본 논문에서는 다입력 퍼지 로직 시스템에서 생기는 퍼지 규칙수의 기하급수적 증가를 막기 위하여, 주어진 퍼지 시스템의 THEN 부분을 이용하여 퍼지 규칙 벡터를 정의하고, 이를 이용하는 2계층의 계층 퍼지 시스템으로 변환하는 방법을 제시한다. 여기에서, 1번째 계층에서는 주어진 퍼지 시스템으로부터 생성되는 일차독립의 퍼지 규칙 벡터를 사용하고, 2계층에서는 1계층에서 사용된 퍼지 규칙 벡터들의 선형 합을 사용한다. 변환된 2계층의 퍼지 시스템은 주어진 퍼지 시스템과 동일한 근사 능력을 가질 뿐 아니라, 더 적은 수의 퍼지 규칙을 가짐을 보인다.

• Journal of Information Processing Systems
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• 제9권4호
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• pp.575-591
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• 2013

Most of the edge detection methods available in literature are gradient based, which further apply thresholding, to find the final edge map in an image. In this paper, we propose a novel method that is based on fuzzy logic for edge detection in gray images without using the gradient and thresholding. Fuzzy logic is a mathematical logic that attempts to solve problems by assigning values to an imprecise spectrum of data in order to arrive at the most accurate conclusion possible. Here, the fuzzy logic is used to conclude whether a pixel is an edge pixel or not. The proposed technique begins by fuzzifying the gray values of a pixel into two fuzzy variables, namely the black and the white. Fuzzy rules are defined to find the edge pixels in the fuzzified image. The resultant edge map may contain some extraneous edges, which are further removed from the edge map by separately examining the intermediate intensity range pixels. Finally, the edge map is improved by finding some left out edge pixels by defining a new membership function for the pixels that have their entire 8-neighbourhood pixels classified as white. We have compared our proposed method with some of the existing standard edge detector operators that are available in the literature on image processing. The quantitative analysis of the proposed method is given in terms of entropy value.