• 수산해양기술연구
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• 제30권3호
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• pp.189-198
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• 1994

This paper describes the model of a simplified trawl system and a control method by using fuzzy algorithm in controlling the depth of trawl gear. Fuzzy logic control rules are sets of linguistic expression that are used by an experienced performer in real operation. For real time processing of the control rules, the look-up tables are used. Computer simulation results indicate that the proposed fuzzy controller shows fast response with minimum steady-state error and robustness properties to the simulated disturbance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.218-220
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• 1993

This paper deals with a self-tuning fuzzy controller. The fuzzy controller is constructed with linguistic rules which consist of the fuzzy variables and fuzzy sets. Each of fuzzy sets is characterized by a membership function. The tuning fussy controller has paramemters to effect control output. In this paper we propose tuning method for the scaling factor. Computer simulations carried out on a second-order process will show how the present tuning approach improves the transient and steady-state characteristics of the overall system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.801-803
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• 1995

This paper presents the linearized fuzzy modeling technique of nonlinear dynamical system and the stability analysis of fuzzy control system. Firstly, the nonlinear system is partitionized by multiple linear fuzzy subcontrol systems based on fuzzy linguistic variables and fuzzy rules. Secondly, the disturbance adaptation controllers which guarrantee the global asymptotic stability of each fuzzy subsystem by an optimal feedback control law are designed and the stability analysis procedures of the total fuzzy control system using Lyapunov functions and eigenvalues are discussed in detail through a given illustrative example.

• 한국산업정보학회논문지
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• 제6권3호
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• pp.35-43
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• 2001

이 논문에서는 WBI(Web-Based Instruction) 시스템의 영역 독립적인 학습자 모듈을 구축하는데 있어 핵심이 되는 요소를 영역 전문가가 쉽게 입력할 수 있도록 하기 위하여 퍼지이론의 언어 변수 개념을 도입한 학습자 응답 진단 공식을 제안한다. 또한 학습자의 인지 상태를 추론하는 규칙을 영역 전문가가 언어변수를 입력하여 구축할 수 있도록 하고 이 규칙을 이용하여 학습자의 인지 상태를 추론할 수 있도록 학습자 모듈을 설계한다.

• 전자공학회논문지B
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• 제31B권10호
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• pp.53-66
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• 1994

In this paper, a fuzzy expert system is developed for fault diagnoisis of a drum-type boiler system in fossil power plants. The develped fuzzy espert system is composed of knowledge base, fuzzification module, knowledge base process module, knowledge base management module, inference module, and linguistic approximation module. The main objective of the fuzzy expert system is to check the states of the system including the drum level and detect faults such as the feedwater flow sensor fault, feedwater flow control valve fault, and water wall bube rupture. The fuzzy expert system diagnoses faults using process values, manipulated values, and knowledge base which is built via interviews and questionaries with the experts on the plant operations. Finally, the validity of the developed fuzzy expert system is shown via experiments using the digital simulator for boiler system is Seoul Power Plant Unit 4.

• 지능정보연구
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• 제12권3호
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• pp.15-32
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• 2006

본 논문에서는 각 대안의 속성 평가와 속성 자체의 중요도에 대한 평가에 있어 불명료한 선호정보 형태로 주어진 경우, linguistic quantifier를 통한 퍼지논리를 활용하여 그룹의사결정을 지원하는 방법을 제시하였다. 불명료한 선호정보는 의사결정 관련 문헌에서 의사결정자에게 요구되는 선호정보 명시의 부담을 줄여주고, 판단의 모호성을 받아들이고자 하는 시각으로서 다뤄져 왔다. 그러나 불명료한 유형의 선호정보를 허용할 경우 의사결정그룹이 원하는 대안의 명확한 선택이 보다 어려워진다. 따라서 추가적인 정보획득을 위한 의사결정자들과의 상호작용이 요구되지만, 이는 불명료한 선호정보를 허용하였던 초기의 취지를 반감시킬 뿐더러, 반드시 최적의 대안을 보장하는 것도 아니다. 이러한 상황을 타계하기 위하여, fuzzy majority의 의미를 반영하고 있는 linguistic quantifier를 활용함으로써 satisfying solution을 구하는 절차를 제시하였다. 이는 mathematical programming을 활용한 의사결정 기법과 다수의 객체를 집성하기 위한 개략적 해법을 결합한 접근방식이다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권1호
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• pp.50-55
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• 2004

We propose an intgrated Gill environment system having only integer fuzzy operations in the consequent part and the defuzzification stage. In this paper, we also propose an integrated Gill environment system with 4 parallel fuzzy processing units to be operated in parallel on the classification of the sensed image data. In this, we solve the problems of taking longer times as the fuzzy real computations of [0, 1] by using the integer pixel conversion algorithm to convert lines of each fuzzy linguistic term to the closest integer pixels. This procedure is performed automatically in the GUI application program. As a Gill environment, PCI transmission, image data pre-processing, integer pixel mapping and fuzzy membership tuning are considered. This system can be operated in parallel manner for MIMO or MISO systems.

• 한국자동차공학회논문집
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• 제2권5호
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• pp.23-29
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• 1994

The design procedure for fuzzy logic controller depends on the expert's knowledge or trial and error. Moreover, it is very difficult to guarantee the stability and robustness of the system due to the linguistic expression of fuzzy control. However, fuzzy logic control has succeeded in many control problems that the conventional control theory has difficulties to deal with. As a result, this control theory is applied to the engine control system which a mathematical model is difficult. In this study, the fuzzy logic is applied to obtain the gain of PI control at idle speed control system, and a simple engine model is developed in order to perform simulation. Experimental results show that the response to reach the target engine speed at idle speed control system is improved by adopting the gain obtained with fuzzy logic.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.79-86
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• 1999

This paper aims to propose a method that helps maintenance engineers to evaluate the damage states of bridge systems by using a Fuzzy Fault Tree Analysis(FFTA). It may be stated that Fuzzy Fault Tree Analysis may be may useful for the systematic md rational condition and safety assessment for real bridge systems problems because the approach is able to effectively deal with all the related bridge system damages in terms of the linguistic variables that incorporate systematically experts experiences and subjective judgement.

• 대한전기학회논문지
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• 제43권4호
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• pp.627-637
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• 1994

In this study, a predictive fuzzy control algorithm to supervise the elevator system with plural cars is developed and its performance is evaluated. The proposed algorithm is based on fuzzy in-ference system to cope with multiple control objects and uncertainty of system state. The control objects are represented as linguistic predictive fuzzy rules and simplified reasoning method is utilized as a fuzzy inference method. Real-time simulation is performed with respect o all possible modes of control, and the resultant controls ard predicted. The predicted rusults are then utilized as the control in-puts of the fuzzy rules. The feasibility of the proposed control algorithm is evaluated by graphic simulator on computer. Finallu, the results of graphic simulation is compared with those of a conventional group control algorighm.