Journal of Intelligent & Fuzzy Systems - Volume 30, issue 1

Authors: Babakordi, F. | Allahviranloo, T. | firozja, M. Adabitabar

Article Type: Research Article

Abstract: In this paper, the fuzzy dual matrix system as A x ˜ + B ˜ = C x ˜ + D ˜ in which A , C are n  × n crisp matrices and B ˜ , D ˜ are n  × n LR fuzzy matrices is studied. To obtain the solution of fuzzy dual system, we initially solve 1-cut and use minimization problem to calculate the spreads. Afterwards, we explain the relationship between the solutions of the systems of A x ˜ + B ˜ …= C x ˜ + D ˜ and ( A - C ) x ˜ = ( D ˜ ⊖ h B ˜ ) . Finally, some examples are solved to illustrate the proposed method. Show more

Keywords: Fuzzy number, optimization, fuzzy dual matrix system, linear programming

DOI: 10.3233/IFS-151781

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 1, pp. 575-581, 2016

Authors: Ban, Adrian I. | Ban, Olimpia I. | Tuşe, Delia A.

Article Type: Research Article

Abstract: A successful indirect method to calculate the importance of the attributes in services is that of correlation between the performance of attributes and the overall satisfaction such as they are perceived by customers. Often, in practice, the input data must be considered as fuzzy numbers, therefore it is completely justified our aim in the present paper, to give an indirect method of calculation of the importance of attributes in the fuzzy case, based on the correlation coefficient. The main benefits are related especially with the importance-performance analysis and multicriteria decision making methods. The effective computation is based on the Zadeh’s …extension principle. The expected value, as a very simple and with suitable properties characteristic associated to a fuzzy number, is used for defuzzification and an immediate interpretation of the results. A practical method, algorithms and illustrative examples are given. The results of a survey with respect to the quality of hotel services in Oradea (Romania) are processed in accordance with our method. Show more

Keywords: Fuzzy number, trapezoidal fuzzy number, fuzzy importance, correlation coefficient, expected value

DOI: 10.3233/IFS-151840

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 1, pp. 583-596, 2016

Authors: Sambariya, Dhanesh K. | Prasad, Rajendra

Article Type: Research Article

Abstract: In this paper the performance analysis of an interval type-2 fuzzy logic controller (IT2 FLC) as a power system stabilizer (PSS) is carried out. The input signals to the controller are considered as speed deviation and acceleration. The application of IT2 FLC as PSS (IT2 FPSS) is considered to improve small signal stability of power system. It is considered for three different benchmark systems such as single-machine infinite-bus (SMIB), two-area four-machine and IEEE ten-machine thirty nine-bus power system. The performance with IT2 FPSS is compared against the performance of the power system without PSS, with conventional PSS (CPSS) and with …fuzzy PSS (FPSS). The application of IT2 FPSS is extended to two-area four-machine ten-bus and IEEE New England ten-machine thirty nine-bus power system and speed response comparison is carried out with FPSS. The superiority of performance with IT2 FPSS over type-1 FPSS is validated in terms of ITAE, IAE and ISE. Show more

Keywords: Power system stabilizer, fuzzy logic based power system stabilizer (FPSS), interval type-2 fuzzy power system stabilizer (IT2 FPSS), conventional PSS (CPSS), single-machine infinite-bus (SMIB), two-area four-machine power system, IEEE New England ten-machine thirty nine-bus power system

DOI: 10.3233/IFS-151825

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 1, pp. 597-612, 2016

Authors: Yi, Hak | Ahn, Min Sung | Hong, Dennis W.

Article Type: Research Article

Abstract: This paper presents an adaptive Fuzzy-PI control strategy that incorporates a humanoid’s upper body rotational motion when controlling its redundant arm. Essentially, fuzzy logic interconnects two different dimensional information by utilizing a humanoid’s angular momentum error at the torso to actively adjust its end-effector’s control parameters (PI) at every loop. The results from two different simulations show that the tracking errors of the proposed Fuzzy-PI scheme is relatively smaller than those of the conventional method. These results imply that Fuzzy-PI can partially compensate for errors in one dimension (end-effector) by taking into account the state of another dimension (torso).

Keywords: Adaptive Fuzzy-PI, humanoid, manipulation, redundant arm, full-body balance

DOI: 10.3233/IFS-151885

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 1, pp. 613-621, 2016