Journal of Intelligent & Fuzzy Systems - Volume 30, issue 3

Authors: Bakhoda, Omid Zhoulai | Menhaj, Mohammad Bagher | Gharehpetian, Gevork B.

Article Type: Research Article

Abstract: In this paper, a comparison between fuzzy logic controller (FLC) and conventional proportional-integral controller (PIC) is presented for a connected PV array system to utility grid via a three-phase line-commutated inverter. The main objective of the controller is providing maximum power for utility grid in different solar radiation conditions. The simulink model of the studied schemes is built using MATLAB/PSB for generating firing pulses of the thyristors in the inverter by applying PIC and FLC methods separately. Three different radiation conditions are examined on both controller which are constant solar radiation, step solar radiation and a combination of step and …ramp scheme. According to simulations, FLC dominates PIC for all radiation types and in many important aspects. Some of these aspects could be named as, extracting power from PV array, providing active power for grid, shape of output current of inverter, shape of grid current waveform and total harmonic distortion (THD) of these currents. Show more

Keywords: Photovoltaic array, maximum power point tracking, fuzzy logic controller, proportional integral controller

DOI: 10.3233/IFS-152049

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1353-1366, 2016

Authors: Kamran, Rahim | Rezaei, Mehdi | Fani, Davoud

Article Type: Research Article

Abstract: Variable bit rate encoded video bit streams are suitable for a wide range of high delay applications such as video streaming applications. In these applications, the visual quality of encoded video and the buffering constraint are concerned during encoding at the same time. In this paper, a fuzzy video rate controller for variable bit rate applications of the new high efficiency video coding (HEVC) standard is proposed. The proposed controller considers a given buffer size and a long-term target bit rate as controlling constraints. It provides a variable bit rate video bit stream by controlling the quantization parameter (QP) at …frame-level. The bitrate of each frame is controlled by a fuzzy controller to minimize the fluctuations of QP and PSNR that leads to high visual quality. The proposed algorithm is implemented on the HEVC standard reference software (HM) and experimental results show that it can provide an average quality, in terms of PSNR, similar to the HM rate controller and constant QP case while the buffer constraint is completely obeyed. Also in comparison with the HM rate controller, the fluctuation of QP and PSNR are less in the proposed algorithm that means a higher visual quality. Show more

Keywords: Bit rate, fuzzy, H.265/HEVC, rate control, variable, video

DOI: 10.3233/IFS-152050

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1367-1375, 2016

Authors: Mansouri, M. | Teshnehlab, M. | Shoorehdeli, M. Aliyari

Article Type: Research Article

Abstract: This study presents a novel indirect adaptive hierarchical fuzzy sliding mode controller for a class of high-order SISO nonlinear systems in normal form with unknown functions in the presence of bounded disturbance. The hierarchical fuzzy system is able to reduce the number of rules and parameters with respect to ordinary fuzzy systems. On-line tuning algorithm for consequent part parameters of fuzzy rules in different layer of hierarchical fuzzy system is derived using defined Lyapunov function. Two theorems are proved to show that the suggested adaptive schemes can achieve asymptotically stable tracking of a reference input with guarantee of the bounded …system signals. One for unity control gain and the other for non-unity control gain. To show the effectiveness of the proposed method, control of three systems are considered in the simulations. The simulations results demonstrate the validity, efficiency and feasibility of the proposed approach to control of nonlinear dynamic system. Show more

Keywords: Sliding mode control, hierarchical fuzzy system, indirect adaptive control, adaptation laws, Lyapunov function and control gain

DOI: 10.3233/IFS-152051

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1377-1391, 2016

Authors: Vahid, Masoud Zahedi | Sadegh, Mahmoud Oukati

Article Type: Research Article

Abstract: Loss reduction planning is considered one of the most significant and sensitive distribution designing system. The planning process to reduce losses along with distributed generation sources results in a non-convex, non-linear optimization problem, mixed with integer variables, which requires complicated calculations. To solve this problem, novel optimization algorithms such as harmony Search (HS) algorithm can be used for different optimization problems. This paper presents an effective intelligent optimization method to solve the network reconfiguration problem in the presence of distributed generation (DG) with an objective of minimizing real power loss and improving voltage profile in distribution system using new set …of harmony search algorithms, called self-adaptive. To verify the efficiency of the algorithm the results have been analyzed in the IEEE standard system. The results show the strength, appropriate efficiency and superior performance of this algorithm in comparison to the original harmony Search algorithm and other optimization algorithms as well. Show more

Keywords: Loss reduction, reconfiguration, self-adaptive harmony search algorithm, distributed generation, optimization

DOI: 10.3233/IFS-152052

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1393-1402, 2016

Authors: Fakhrzad, Mohammad Bagher | Rahdar, Moheb Ali

Article Type: Research Article

Abstract: This paper presents a method for hybridizing artificial hormones controller with type-2 fuzzy controller. Artificial hormones robot control system provides the ability to self-control, while the fuzzy controller is appropriate for nonlinear systems with time delay and dynamic systems. This paper presents three feasible scenarios of hybridizing two controllers. Controller performance indicators, such as settling time, overshoot, steady state error, and integrals known as feedback error performance indices (integral absolute error [IAE], integral squared error [ISE], integral time-weighted absolute error [ITAE], integral of time multiplied by the squared error [ITSE]), were studied and compared. The results of the hybrid controller …for each of the scenarios show that it has better performance than any of the fuzzy and artificial hormone controllers alone. Energy consumption in the base and hybrid controllers was compared. The results show that the energy consumption for the hybrid controller is 20 to 30% less than the base controller. Show more

Keywords: Robot control system, hybrid controller, artificial hormone controller, fuzzy type-2 controller, performance indices

DOI: 10.3233/IFS-152053

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1403-1410, 2016

Authors: Tavakol-Sisakht, S. | Barakati, S. Masoud

Article Type: Research Article

Abstract: In electric vehicles, the battery is exposure to an excessive stress because of continuously charging and discharging. In this paper, a hybrid energy storage system (HESS) combined of supercapacitors (SC) and batteries is deployed. An energy management strategy based on fuzzy logic controller (FLC) and rule based controller (RBC) are proposed to mitigate the high stress problem and increase the battery lifetime. The battery and SC sizes are optimized based on a power demand profile. Based on simulation results, three different HESSs along with FLC and RBC are compared, in their SC voltages and battery currents viewpoints, and the best …one is introduced. FLC has advantageous to alleviate battery current fluctuations in comparison with RBC, but RBC has higher battery lifetime. Show more

Keywords: Hybrid energy storage system (HESS), fuzzy logic controller (FLC), electric vehicles, energy management strategy

DOI: 10.3233/IFS-152054

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1411-1420, 2016

Authors: Maleki, Hamid Reza | Karimidehkordi, Elaheh

Article Type: Research Article

Abstract: Natural disasters such as earthquakes have a strong impact on communications systems. Traditionally, Base Station of phone systems are set up without special consideration of disasters. In this paper, a multi objective model is considered for fortification of Base Station against natural disasters. The goal of this model is to maximize service coverage, before and after disasters. At first we use fuzzy set theory and fuzzy programming to convert the multi objective programming (MOP) problem to single objective programming (SOP) problem. Then, because this problem is NP- hard, it solved by Genetic and GRASP algorithms. These metaheuristics algorithms are compared …together on instances of this problem. Show more

Keywords: Multi objective, fortification, metaheuristic, fuzzy programming

DOI: 10.3233/IFS-152055

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1421-1427, 2016

Article Type: Other

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1429-1429, 2016

Authors: Hao, Pei-Yi

Article Type: Research Article

Abstract: In this paper, we develop a novel support vector algorithm with fuzzy hyperplane for pattern classification. We first introduce the concepts of fuzzy hyperplane and fuzzy linear separability. Then, the proposed approach seeks a fuzzy hyperplane that best separates the positive class from the negative class with the widest margin in the feature space. Further, the decision function of the proposed approach is generalized so the values assigned to the individuals fall within a specified range and indicate the membership degree of these individuals in a given category. This integration preserves the benefits of fuzzy set theory and SVM theory, …where the use of the fuzzy hyperplane provides the SVM with effective means for capturing the approximate, imprecise nature of the real world. On the other hand, the SVM provides the advantage to minimize the structural risk and effectively generalize the unseen data. Experimental results are then presented which indicate the performance of the proposed approach. Show more

Keywords: Support vector machine (SVM), maximal-margin classifier, fuzzy set theory, fuzzy classifier

DOI: 10.3233/IFS-151852

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1431-1443, 2016

Authors: Wang, Bingkun | Huang, Yongfeng | Yuan, Zhigang | Li, Xing

Article Type: Research Article

Abstract: With the rapid growth of user-generated contents online, unsupervised methods which do not need to use labeled training data have become increasingly important in sentiment classification. But the performance of unsupervised methods is unsatisfactory. This is because sentence structure and ambiguity of sentiment intensity are usually ignored in existing unsupervised methods. To address these problems, we propose a multi-granularity fuzzy computing model which involves two innovations. Firstly, we come up with a multi-granularity computing method to compute sentiment intensity of reviews. To be specific, we deconstruct those reviews into three levels of language units—words, phrases and sentences, and consequently manage …to compute the sentiment intensity of reviews by combining rule-based methods and statistic-based methods. Secondly, a fuzzy classifier is constructed to solve the ambiguity of sentiment intensity. Furthermore, two different self-supervised methods using pseudo-labeled training data are proposed to learn the optimum parameters of the fuzzy classifier. Experimental results in four different datasets prove that our model improves 6.25% more accuracy on average than the competitive baselines in sentiment classification of Chinese reviews. Show more

Keywords: Sentiment classification, unsupervised methods, fuzzy computing model, multi-granularity computing

DOI: 10.3233/IFS-151853

Citation: Journal of Intelligent & Fuzzy Systems, vol. 30, no. 3, pp. 1445-1460, 2016