• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.3
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• pp.188-199
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• 2014

Although the fuzzy logic controller is superior to the proportional integral derivative (PID) controller in motor control, the gain tuning of the fuzzy logic controller is more complicated than that of the PID controller. Using mathematical analysis of the proportional derivative (PD) and fuzzy logic controller, this study proposed a design method of a fuzzy logic controller that has the same characteristics as the PD controller in the beginning. Then a design method of a fuzzy logic controller was proposed that has superior performance to the PD controller. This fuzzy logic controller was designed by changing the envelope of the input of the of the fuzzy logic controller to nonlinear, because the fuzzy logic controller has more degree of freedom to select the control gain than the PD controller. By designing the fuzzy logic controller using the proposed method, it simplified the design of fuzzy logic controller, and it simplified the comparison of these two controllers.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1281-1284
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• 1993

By the exponential representation form (EF) for fuzzy logic, any fuzzy value a (in fuzzy valued logic or fuzzy linguistic valued logic) can be represented as Bc, where B is called the truth base and C the confidence exponent. This paper will propose the basic concepts of this form and discuss its interesting properties. By using a different truth base, the exponential form can be used to represent the positive and the negative logic in fuzzy valued logic as well as in fuzzy linguistic valued logic. Some Simple application examples of EF for approximate reasoning are also illustrated in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2270-2273
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• 2003

Fuzzy logic control has been widely implemented in air conditioning and ventilation systems which has uncertainty or high robust system. Since the dynamic behaviors of the systems contain complexity and uncertainty in its parameters , several fuzzy logic controllers had been implemented to control room temperature in the field of air conditioning system. In this paper, the fuzzy logic control has been developed to control room temperature and humidity in the precision air conditioning systems. The nonlinear mathematical model was formulated using energy and continuity equations. MATLAB was used to simulate the fuzzy logic control of the multi-variable air conditioning systems. The simulation results show that fuzzy logic controller can reduce the steady-state errors of the room temperature and relative humidity in multivariable air conditioning systems. The offset are less than 0.5 degree Celsius and 3 percent in relative humidity respectively under random step disturbance in heating load and moisture load respectively

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.993-996
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• 1993

This paper addresses the structure and its associated learning algorithms of a feedforward multi-layered connectionist network, which has distributed learning abilities, for realizing the basic elements and functions of a traditional fuzzy logic controller. The proposed neural-network-based fuzzy logic control system (NN-FLCS) can be contrasted with the traditional fuzzy logic control system in their network structure and learning ability. An on-line supervised structure/parameter learning algorithm dynamic learning algorithm can find proper fuzzy logic rules, membership functions, and the size of output fuzzy partitions simultaneously. Next, a Reinforcement Neural-Network-Based Fuzzy Logic Control System (RNN-FLCS) is proposed which consists of two closely integrated Neural-Network-Based Fuzzy Logic Controllers (NN-FLCS) for solving various reinforcement learning problems in fuzzy logic systems. One NN-FLC functions as a fuzzy predictor and the other as a fuzzy controller. As ociated with the proposed RNN-FLCS is the reinforcement structure/parameter learning algorithm which dynamically determines the proper network size, connections, and parameters of the RNN-FLCS through an external reinforcement signal. Furthermore, learning can proceed even in the period without any external reinforcement feedback.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.2
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• pp.126-131
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• 2015

Studies on the control of inverted pendulum type systems have been widely reported. This is because this type of system is a typical complex nonlinear system and may be a good model to verify the performance of a proposed control system. In this paper, we propose the design of two fuzzy logic control systems for the control of a Segway mobile robot which is an inverted pendulum type system. We first introduce a dynamic model of the Segway mobile robot and then analyze the system. We then propose the design of the fuzzy logic control system, which shows good performance for the control of any nonlinear system. In this paper, we here design two fuzzy logic control systems for the position and balance control of the Segway mobile robot. We demonstrate their usefulness through simulation examples. We also note the possibility of simplifying the design process and reducing the computational complexity. This possibility is the result of the skew symmetric property of the fuzzy rule tables of the system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.917-920
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• 1993

Various forms of hardware alternatives exist for the implementation of fuzzy logic controllers. In this paper, we describe a systematic framework for realizing fuzzy heuristics on programmable-logic-devices. Our approach is suitable for the automated development of fuzzy logic controllers.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.321-324
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• 2008

Type-2 퍼지 집합은 Type-1 퍼지 집합에서는 다루기 어려운 언어적인 불확실성을 더욱 효과적으로 다룰 수 있다. TSK 퍼지 로직 시스템(TSK Fuzzy Logic Systems; TSK FLS)은 Mamdani 모델과 함께 가장 널리 사용되는 FLS이다. 본 연구의 Interval Type-2 TSK FLS 모델은 전반부에서 Type-2 퍼지 집합을 이용하고 후반부는 계수가 상수인 1차식을 사용한다. 전반부의 파라미터는 오류역전파 방법(Back-propagation)을 통한 학습으로 결정되고, 후반부 파라미터(계수)들은 Least squre method(LSM)를 사용하여 결정된 값을 사용하여 모델을 구축한다. 본 논문에서는 Type-1 TSK FLS과 Type-2 TSK FLS의 성능을 가스로 공정 데이터를 적용하여 비교 분석한다. 또한 랜덤 화이트 가우시안 노이즈를 추가한 테스트 데이터를 사용하여 노이즈에 대한 성능을 분석한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.329-332
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• 2008

Type-2 퍼지 집합은 언어적인 불확실성을 다루기 위하여 Zadeh에 의해 제안되었고 Mendel과 Kamik에 의해 이론이 체계화 되었다. TSK 퍼지 로직 시스템(TSK Fuzzy Logic Systems; TSK FLS)은 Mamdni 모델과 함께 가장 널리 사용되는 퍼지 로직 시스템이다. 본 논문에서는 Type-2 퍼지 집합을 이용하여 전반부 멤버쉽 함수를 구성하고 후반부 다항식 함수를 상수와 1차식, 2차식으로 확장한 다항식 Type-2 TSK FLS 설계한다. 또한 가스로 공정 데이터에 응용하여 후반부 다항식의 변화에 따른 Type-2 TSK FLS의 특징을 비교 분석 할 뿐 만 아니라 테스트 데이터에 노이즈를 첨가하여 노이즈에 따른 Type-l TSK FLS과 Type-2 TSK FLS의 특성을 분석한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.311-312
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• 2008

Fuzzy logic is introduced by Zadeh in 1965. It has been continuously developed by many mathematicians and knowledge engineers all over the world. A lot of papers concerning with the history of mathematics and the mathematical education related with fuzzy logic, but there is no paper concerning with Zadeh. In this article, we investigate his life and papers about fuzzy logic. We also compare two-valued logic, three-valued logic, fuzzy logic, intuisionistic logic and intuitionistic fuzzy sets. Finally we discuss about the expression of intuitionistic fuzzy sets.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.468-477
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• 1994

Existing fuzzy control methods do not perform well when applied to systems containing nonlinearities arising from unkonwn deadzones. In particular, we show that a conventional fuzzy logic controller applied to a system with a deadzone suffers from poor transient performance and a large steady-syate error. In this paper, we propose a novel two-layered fuzzy logic controller for controlling systems with deadzones. The two-layered control structure consists of a fuzzy logic-based precompensator followed by a conventional fuzzy logic controller. Our proposed controller exhibits superior transient and steady-state performance compared to conventional fuzzy controllers. In addition, the controller is robust to variations in deadzone nonlinearities. We illustrate the effectiveness of our scheme using computer simulation examples.