• Journal of applied mathematics & informatics
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• v.20 no.1_2
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• pp.523-533
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• 2006

In this paper we have a common fixed point theorem which is a generalization of result of [12] and we characterize the conditions for continuous self mappings S, T of complete fuzzy metric space (X, M, *) have a uniqe common fixed point in X.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.3
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• pp.149-152
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• 2011

In this paper, we obtain common fixed point theorem for common property(E.A.) and weakly compatible functions in intuitionistic fuzzy metric space.

• Korean Journal of Mathematics
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• v.20 no.1
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• pp.91-106
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• 2012

In this paper, we prove the Hyers-Ulam stability of the Jensen functional equation in fuzzy Banach algebras by using fixed point method and by using direct method.

• Communications of the Korean Mathematical Society
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• v.22 no.3
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• pp.429-440
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• 2007

In this paper, a common fixed point theorem for weak compatible maps in complete fuzzy metric spaces is proved.

• Communications of the Korean Mathematical Society
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• v.25 no.1
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• pp.59-68
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• 2010

In this paper, we prove common fixed point theorems for semi-compatible mappings on intuitionistic fuzzy metric space with different some conditions of Park and Kim [10]. This research extended and generalized the results of Singh and Chauhan [14].

• Kyungpook Mathematical Journal
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• v.45 no.1
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• pp.115-121
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• 2005

Using the concept of fuzzy points, the notions of fuzzy point BCC-(sub) algebras, quasi BCC-(sub)algebras and quasi BCC-ideals are introduced. Some characterizations of them are discussed.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.1
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• pp.1-14
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• 2019

We prove the generalized Hyers-Ulam-Rassias stability problem of the quadratic functional equation with involution in the fuzzy quasi ${\beta}$-normed space by using the fixed point method.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.767-778
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• 2008

Comparison between two or more fuzzy numbers, along with their ranking, is an important subject discussed in scholarly articles. We endeavor in this paper to present a simple yet effective parametric method for comparing fuzzy numbers. This method offer significant advantages over similar methods, in comparing intersected fuzzy numbers, rendering the comparison between fuzzy numbers possible in different decision levels. In the process, each fuzzy number will be given a parametric value in terms of $\alpha$, which is dependent on the related $\alpha$-cuts. We have compared this method to Cheng's centroid point method [5] (The relation of calculating centroid point of a fuzzy number was corrected later on by Wang [12]). The proposed method can be utilized for all types of fuzzy numbers whether normal, abnormal or negative.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.164-169
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• 1995

Fictitious experiment to control extrusion process was carried out using the fuzzy theory. Algorithm of the fuzzy logic controller(FLC) was made based on the general principles of extrusion. In the simulation, at first, thickness of extrudate was measured as feedback input variable. Secondly, a set point of screw speed was determined as output variable of extruder operating condition through FLC. Finally, the thickness of extrudate was controlled as a given set point. Barrel heater was simply controlled as on/off state, which was not fuzzy controlled.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.9-18
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• 2014

This paper proposes the fuzzy PI controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation. The MPPT control is a very important technique in order to increase an output and efficiency of the photovoltaic system. The conventional perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, this paper proposes the MPPT control using the fuzzy PI controller that can be improve a MPPT control performance. The fuzzy PI controller is adjusted a input of PI controller by fuzzy control and compensated a cumulative error of fuzzy control by PI controller. The fuzzy PI MPPT control is compared to conventional PO and IC MPPT method for various temperature and radiation condition. This paper proves the validity of the fuzzy PI controller using these results.