Journal of Intelligent & Fuzzy Systems - Volume 29, issue 2

Authors: Xu, Jinquan | Chen, Ye-Hwa | Guo, Hong

Article Type: Research Article

Abstract: We propose an optimal approach to a new control design for fuzzy dynamical systems in this paper. Consider the system containing uncertainty, which may includes the unknown system parameter and input disturbance. And the uncertainty can be prescribed with a fuzzy set. A new class of factional-type robust controls are proposed, whose structure is deterministic and is not if-then rule-based. Furthermore, the control gain design is formulated as a constrained optimization problem, which minimizes both the average fuzzy performance and control effort. We show that the solution of this optimization problem always exists and is unique. And the closed-form solution …and closed-form minimum cost are derived. The resulting control can guarantee the uniform boundedness and uniform ultimate boundedness of the uncertain system, while minimizing both the average fuzzy performance and control effort. Show more

Keywords: Fuzzy dynamical systems, fuzzy set theory, robust control, uniform boundedness, uniform ultimate boundedness, optimization

DOI: 10.3233/IFS-141316

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 553-569, 2015

Authors: Vahedi, Mojtaba | Zarif , Mohammad Hadad | Kalat, Ali Akbarzadeh

Article Type: Research Article

Abstract: This paper presents a novel stable speed control approach for induction motors (IMs) using approximation capability of neural networks and fuzzy systems. Considering the fact that most of previous works are based on direct torque control (DTC) and field oriented control (FOC) without any stability analysis, the main contribution of this paper is developing a simple speed controller for medium sized IMs with guaranteed stability. The uncertainties including parametric variations, the external load disturbance and unmodeled dynamics is estimated and compensated by designing a neuro-fuzzy controller. The reconstruction error of the neuro-fuzzy estimator is compensated in order to guarantee the …asymptotic convergence of the speed tracking error using Barbalat’s lemma. Finally, simulation results show that the proposed controller provides high-performance characteristics and is robust with regard to plant parameter variation, external load and input voltage disturbance. Show more

Keywords: Induction motor, neuro-fuzzy systems, uncertainty estimation and compensation, reconstruction error, Barbalat’s lemma

DOI: 10.3233/IFS-141326

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 571-581, 2015

Authors: Zhang, Xiaohong | Zheng, Yue

Article Type: Research Article

Abstract: Ying’s model of linguistic quantifiers based on Sugeno integral is generalized to interval-valued intuitionistic Sugeno integral, the truth value of a quantified proposition is evaluated by using interval-valued intuitionistic Sugeno integral. Some logical properties of linguistic quantifiers in this model are discussed, and some application examples in uncertainty decision making and linguistic summarization of data are presented.

Keywords: Fuzzy set, Intuitionistic fuzzy set, fuzzy measure, Sugeno integral, interval-valued intuitionistic fuzzy quantifier

DOI: 10.3233/IFS-141334

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 583-592, 2015

Authors: Bashar, M. Abul | Hipel, Keith W. | Kilgour, D. Marc | Obeidi, Amer

Article Type: Research Article

Abstract: Coalition fuzzy stability concepts are developed within the Fuzzy Preference Framework for the Graph Model for Conflict Resolution to investigate how decision makers can cooperate. The objective is to identify favorable outcome(s) in a multiple participant-multiple objective decision problem with fuzzy preference information. More specifically, coalition versions of fuzzy Nash stability, fuzzy general metarationality, fuzzy symmetric metarationality, and fuzzy sequential stability are proposed. They constitute a natural generalization of the corresponding non-cooperative fuzzy preference-based definitions for Nash stability, general metarationality, symmetric metarationality, and sequential stability, respectively. Coalition fuzzy stability definitions are employed to analyze an actual dispute over groundwater contamination …in Elmira, Ontario, Canada, demonstrating how these new concepts can be conveniently applied to practical problems in order to gain valuable strategic insights. Show more

Keywords: Coalitions, graph model, fuzzy preference, fuzzy stability, coalition fuzzy stability

DOI: 10.3233/IFS-141336

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 593-607, 2015

Authors: Mei, Cai | Zaiwu, Gong | Jie, Cao

Article Type: Research Article

Abstract: When different experts have different uncertainty degrees on the phenomenon, several linguistic term sets with different granularity of uncertainty are necessary. In this paper, we deal with the consistency problem with multi-granularity linguistic term sets applied to group decision making. Firstly, we develop a transformation model to maintain the uncertainty degrees of different granularity associated with each expert. We use the uncertain linguistic variables as the unified form. Some computational rules about uncertain linguistic variables are given. Then consistency index of linguistic preference relations based on the distance of a multi-granularity linguistic preference relation is defined. Chi-square statistic is used …to establish the consistency thresholds. Finally two numerical examples are used to show the process and effects of our new proposed method. Show more

Keywords: Multi-granularity linguistic term sets, group decision making (GDM), uncertain linguistic variables, consistency index

DOI: 10.3233/IFS-141340

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 609-618, 2015

Authors: Xu, Yejun | Ma, Feng | Xu, Weijun | Wang, Huimin

Article Type: Research Article

Abstract: Unconventional outburst incidents are unpredictable and also have no emergency plans, they can bring huge economic losses and social issues, so we should find optimal emergency decision scheme. In this paper, we study the group decision making (GDM) problems with incomplete fuzzy linguistic preference relations (FLPRs), and the linguistic information provided by different experts are assessed in linguistic term sets with different granularity. We first develop a four-way procedure to estimate missing preference values when dealing with 2-tuple incomplete FLPRs. We propose the transformation rules for multi-granular FLPRs, and devise a transformation function which satisfies the transformation rules. The transformation …can transform any linguistic term set to another linguistic term set. Furthermore, we study the properties and advantages of the transformation function. Finally, we integrate the revised estimation procedure for incomplete 2-tuple FLPRs and the multi-granular linguistic decision model to deal with emergency decision of unconventional outburst incidents. It is showed that the proposed method is straightforward and without loss of information. Show more

Keywords: Multi-granular linguistic, incomplete FLPRs, unconventional outburst incidents, emergency decision

DOI: 10.3233/IFS-141355

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 619-633, 2015

Authors: Kouchakinejad, Fateme | Khorram, Esmaile | Mashinchi, Mashaalah

Article Type: Research Article

Abstract: An optimization problem of a linear objective function subject to a system of fuzzy relational inequalities based on max-average composition and fuzzy inequality is presented. This problem is converted to a new one with ordinary inequalities by using linear membership functions and Bellman-Zadeh decision. Then, dimension of the last problem is reduced and an algorithm is presented to generate the optimal solution of the initial optimization problem. Two numerical examples are given to illustrate the steps of the algorithm. Some aspects of sensitivity analysis of the problem is investigated.

Keywords: Fuzzy inequality, fuzzy relational inequalities, linear objective function optimization, max-average composition, sensitivity analysis

DOI: 10.3233/IFS-141361

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 635-645, 2015

Authors: Jin, Xin | Shin, Yung C.

Article Type: Research Article

Abstract: The approach of designing a discrete time optimal controller for a nonlinear system represented by a fuzzy model is presented in this paper. A fuzzy model with product inference engine, singleton fuzzifier, center average defuzzifier, and Gaussian membership functions is trained by the orthogonal least square (OLS) learning algorithm based on given input-output data pairs. An optimal control scheme is then formulated based on the fuzzy model. The numerical solution of the problem is achieved by use of a feasible-direction algorithm. To show the effectiveness of the proposed method, the simulation results of three nonlinear optimal control problems are presented. …The results show that the performance of the proposed approach is quite similar to that of optimal control of the system represented by an explicit mathematical model, thus demonstrating the efficacy of the proposed scheme for optimal control of unknown nonlinear systems. Show more

Keywords: Optimal controller, nonlinear system, fuzzy model, feasible-direction algorithm

DOI: 10.3233/IFS-141376

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 647-658, 2015

Authors: Ghosh, Debdas | Chakraborty, Debjani

Article Type: Research Article

Abstract: In this paper, fuzzy geometrical construction and characteristics of fuzzy lines are investigated. A general form of fuzzy lines is proposed. It is shown that a fuzzy line passing through a set of fuzzy points whose cores are collinear is unique. Slope and intercept of a fuzzy line, vertical and perpendicular distances from a fuzzy point to a fuzzy line are also studied. Sup-min composition of fuzzy sets and concepts of same and inverse points in fuzzy geometry are applied to define all the ideas. Proposed general form of fuzzy line is applied to fit a fuzzy line for …a dataset of imprecise locations or fuzzy points. It is shown that the fitted fuzzy line has the minimum sum of square vertical distances between the given fuzzy points and the fitted fuzzy line. Proposed definitions and ideas are supported by several numerical and pictorial illustrations. Show more

Keywords: Fuzzy set, fuzzy number, fuzzy point, same and inverse points, fuzzy line, fuzzy distance, fuzzy line fitting

DOI: 10.3233/IFS-141379

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 659-671, 2015

Authors: Yang, Rong | Wang, Yun | Wang, Zhenyuan

Article Type: Research Article

Abstract: A novel model based on nonlinear integrals is developed for the foreground and background detection. The nonlinear integral based on fuzzy measures, or its generalization, efficiency measure, is modeled as an aggregation tool to fuse the texture and color features of pixels. By setting suitable threshold value, the fusing result is represented as a two-class classifier to determine whether the pixels being considered belong to foreground or background. An optimization program based on genetic algorithm is proposed to retrieve the critical parameters of the efficiency measure with respect to which the nonlinear integral is defined and the threshold value to …classify foreground and background. This method can handle various small variations of background objects and support sensitive detection of moving targets. Experiments results indicate that foreground and background can be separated correctly by using this new model and relevant algorithm. Comparisons with some existing models also verify the performance of the model being presented. Show more

Keywords: Classification, the Choquet integral, foreground detection, background subtraction, fuzzy measure, genetic algorithm

DOI: 10.3233/IFS-141405

Citation: Journal of Intelligent & Fuzzy Systems, vol. 29, no. 2, pp. 673-684, 2015