Journal of Intelligent & Fuzzy Systems - Volume 39, issue 3

Authors: Saqib, Muhammad | Akram, Muhammad | Bashir, Shahida

Article Type: Research Article

Abstract: A bipolar fuzzy set model is an extension of fuzzy set model. We develop new iterative methods: generalized Jacobi, generalized Gauss-Seidel, refined Jacobi, refined Gauss-seidel, refined generalized Jacobi and refined generalized Gauss-seidel methods, for solving bipolar fuzzy system of linear equations(BFSLEs). We decompose n  ×  n BFSLEs into 4n  ×  4n symmetric crisp linear system. We present some results that give the convergence of proposed iterative methods. We solve some BFSLEs to check the validity, efficiency and stability of our proposed iterative schemes. Further, we compute Hausdorff distance between the exact solutions and approximate solution of our proposed schemes. The …numerical examples show that some proposed methods converge for the BFSLEs, but Jacobi and Gauss-seidel iterative methods diverge for BFSLEs. Finally, comparison tables show the performance, validity and efficiency of our proposed iterative methods for BFSLEs. Show more

Keywords: Bipolar fuzzy system of linear equations, generalized Jacobi method, generalized Gauss-sediel method, refined generalized Jacobi method, refined generalized Gauss-seidel method

DOI: 10.3233/JIFS-200084

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 3971-3985, 2020

Authors: Li, Changqing | Zhang, Yanlan | Zhang, Jing

Article Type: Research Article

Abstract: The idea of statistical convergence, which was first introduced by Fast and Steinhaus independently in 1951, has become one of the most active area of research in the field of mathematics. Recently, it has been applied to the realm of metrics by several authors and some useful results have been obtained. However, the existence of non-completable fuzzy metric spaces, in the sense of George and Veeramani, demonstrates that the theory of fuzzy metrics seem to be richer than that of metrics. In view of this, we attempt to generalize this convergence to the realm of fuzzy metrics. Firstly, we introduce …the concept of sts -convergence in fuzzy metric spaces. Then we characterize those fuzzy metric spaces in which all convergent sequences are sts -convergent. Finally, we study sts -Cauchy sequences in fuzzy metric spaces and sts -completeness of fuzzy metric spaces. Show more

Keywords: Fuzzy metric, statistically convergent sequence, statistically Cauchy sequence, statistical completeness, convergence

DOI: 10.3233/JIFS-200148

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 3987-3993, 2020

Authors: Jahan, I. | Manas, A.

Article Type: Research Article

Abstract: In this paper, the concept of a maximal L -subgroup of an L -group has been defined in the spirit of classical group theory. Then, a level subset characterization has been established for the same. Then, this notion of maximal L -subgroups has been used to define Frattini L -subgroup. Further, the concept of non-generators of an L -group has been developed and its relation with the Frattini L -subgroup of an L -group has been established like their classical counterparts. Moreover, several properties pertaining to the concepts of maximal L -subgroups and Frattini L -subgroup have also been investigated. …These two notions have been illustrated through several examples. Show more

Keywords: L-algebra, L-subgroup, generated L-subgroup, normal L-subgroup, maximal L-subgroup, Frattini L-subgroup, non-generators of an L-group

DOI: 10.3233/JIFS-200157

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 3995-4007, 2020

Authors: Zahar Djordjevic, Marija | Simeunovic, Barbara | Nestic, Snezana | Aleksic, Aleksandar | Puskaric, Hrvoje

Article Type: Research Article

Abstract: Improvement of the production process presents a very important management task for both researchers and practitioners and enables a better market position of the enterprise. Key Performance Indicators (KPIs) of the production process can provide useful information on the current state of the ongoing process. In this paper, the relative importance of KPIs and their values at the enterprise level were assessed by the experts and decision-makers. Their estimates are described by the linguistic variables which were modeled by intuitionistic fuzzy numbers. The weights vector of KPIs at the level of the considered enterprise is given by the Fuzzy Analytic …Hierarchical Process (FAHP) with Triangular Intuitionistic Fuzzy Numbers (TIFNs). The rank of enterprises with respect to KPIs’ values and their weights was calculated using the modified TOPSIS with TIFNs. The developed model was tested on 30 enterprises from Serbia, belonging to the sector of small and medium-sized (SME) production enterprises. The improvement strategies of KPIs should be proposed at the level of each enterprise, separately, respecting the KPIs’ values of the first-ranked enterprise. Show more

Keywords: Intuitionistic fuzzy numbers, fuzzy AHP, fuzzy TOPSIS, production process, benchmarking

DOI: 10.3233/JIFS-200159

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4009-4026, 2020

Authors: Runkler, Thomas A.

Article Type: Research Article

Abstract: Fuzzy pairwise preferences are an important model to specify and process expert opinions. A fuzzy pairwise preference matrix contains degrees of preference of each option over each other option. Such degrees of preference are often numerically specified by domain experts. In decision processes it is highly desirable to be able to analyze such preference structures, in order to answer questions like: Which objects are most or least preferred? Are there clusters of options with similar preference? Are the preferences consistent or partially contradictory? An important approach for such analysis is visualization. The goal is to produce good visualizations of preference …matrices in order to better understand the expert opinions, to easily identify favorite or less favorite options, to discuss and address inconsistencies, or to reach consensus in group decision processes. Standard methods for visualization of preferences are matrix visualization and chord diagrams, which are not suitable for larger data sets, and which are not able to visualize clusters or inconsistencies. To overcome this drawback we propose PrefMap, a new method for visualizing preference matrices. Experiments with nine artificial and real–world preference data sets indicate that PrefMap yields good visualizations that allow to easily identify favorite and less favorite options, clusters, and inconsistencies, even for large data sets. Show more

Keywords: fuzzy preference relations, visualization, multidimensional scaling

DOI: 10.3233/JIFS-200189

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4027-4040, 2020

Authors: Liu, Fang | Tan, Xu | Yang, Hui | Zhao, Hui

Article Type: Research Article

Abstract: Intuitionistic fuzzy preference relations (IFPRs) have the natural ability to reflect the positive, the negative and the non-determinative judgements of decision makers. A decision making model is proposed by considering the inherent property of IFPRs in this study, where the main novelty comes with the introduction of the concept of additive approximate consistency. First, the consistency definitions of IFPRs are reviewed and the underlying ideas are analyzed. Second, by considering the allocation of the non-determinacy degree of decision makers’ opinions, the novel concept of approximate consistency for IFPRs is proposed. Then the additive approximate consistency of IFPRs is defined and …the properties are studied. Third, the priorities of alternatives are derived from IFPRs with additive approximate consistency by considering the effects of the permutations of alternatives and the allocation of the non-determinacy degree. The rankings of alternatives based on real, interval and intuitionistic fuzzy weights are investigated, respectively. Finally, some comparisons are reported by carrying out numerical examples to show the novelty and advantage of the proposed model. It is found that the proposed model can offer various decision schemes due to the allocation of the non-determinacy degree of IFPRs. Show more

Keywords: Decision making, intuitionistic fuzzy preference relation (IFPR), inherent property, approximate consistency, priority vector

DOI: 10.3233/JIFS-200200

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4041-4058, 2020

Authors: Ren, Weina | Li, Chengdong | Wen, Peng

Article Type: Research Article

Abstract: As one kind of readily available renewable energy sources, wind is widely used in power generation where wind speed plays an important role. Generally speaking, we need to forecast the wind speed for improving the controllability of wind power generation. However, there exists considerable randomness and instabilities in wind speed data so that it is difficult to obtain accurate forecasting results. In this paper, we propose a novel fuzzy inference method based hybrid model for accurate wind speed forecasting. In this hybrid model, we adopt two strategies to enhance the estimation performance. On one hand, we propose the purification machine …which utilize the Irregular Information Reduction Module (IIRM) and the Irrelevant Variable Reduction Module (IVRM) to reduce the randomness and instabilities of the data and to eliminate the variables with zero or negative effect in the wind speed time series. On the other hand, we adopt the developed Single-Input-Rule-Modules based Fuzzy Inference System (SIRM-FIS), the functionally weighted SIRM-FIS (FWSIRM-FIS) to realize the prediction of wind speed. This FWSIRM-FIS utilizes the multi-variable functional weights to dynamically measure the importance of the input variables so that the input-output mapping can be strengthened and more accurate forecasting results can be achieved. Furthermore, detailed experiments and comparisons are given. Experimental results demonstrate that the proposed FWSIRM-FIS and purification machine contributes greatly to deal with the randomness and instability in the wind speed data and yield more accurate forecasting results than those existing excellent forecasting models. Show more

Keywords: Fuzzy inference system, purification machine, wind speed forecasting, time series prediction

DOI: 10.3233/JIFS-200205

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4059-4070, 2020

Authors: Mohammadzadeh, E. | Muhiuddin, G. | Zhan, J. | Borzooei, R.A.

Article Type: Research Article

Abstract: In this paper, we introduce a new definition for nilpotent fuzzy Lie ideal, which is a well-defined extension of nilpotent Lie ideal in Lie algebras, and we name it a good nilpotent fuzzy Lie ideal . Then we prove that a Lie algebra is nilpotent if and only if any fuzzy Lie ideal of it, is a good nilpotent fuzzy Lie ideal. In particular, we construct a nilpotent Lie algebra via a good nilpotent fuzzy Lie ideal. Also, we prove that with some conditions, every good nilpotent fuzzy Lie ideal is finite. Finally, we define an Engel fuzzy Lie ideal, …and we show that every Engel fuzzy Lie ideal of a finite Lie algebra is a good nilpotent fuzzy Lie ideal. We think that these notions could be useful to solve some problems of Lie algebras with nilpotent fuzzy Lie ideals. Show more

Keywords: Lie algebra, nilpotent Lie algebra, (good nilpotent) fuzzy Lie ideal

DOI: 10.3233/JIFS-200211

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4071-4079, 2020

Authors: Zhang, Tao | Liu, Meng-Qi | Rong, Mei

Article Type: Research Article

Abstract: Dynamic Concept-cognitive Learning (CCL) is an active field in cognitive computing. Decremented concept cognition is an important topic in dynamic CCL. As an important feature of the dynamic CCL, attenuation characteristics have been successfully visualized by concept lattice and three-dimensional attribute topology. However, the existing attenuation characteristic analysis method has limitations to the description of interaction between attributes. A method of attenuation characteristics analysis of concept tree is proposed. The coupling between nodes is discussed from the concept tree, the nodes are decremented according to the coupling relationship, and the corresponding node attenuation rules are discussed according to the different …types of nodes. In this paper, the news attention is the research object. The experimental results show that the attenuation characteristic analysis scheme of the concept tree is feasible. In the process of attenuation, the effect of attribute attenuation on the concept structure can be clearly demonstrated. At the same time, the concept tree can better visualize the process of decremented news attention than the concept lattice and three-dimensional attribute topology. Show more

Keywords: Concept-cognitive learning, formal concept analysis, concept tree, decremented concept cognition, attenuation characteristics

DOI: 10.3233/JIFS-200218

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4081-4094, 2020

Authors: Bagheri Sanjareh, Mehrdad | Nazari, Mohammad Hassan | Gharehpetian, Gevork B. | Hosseinian, Seyed Hossein

Article Type: Research Article

Abstract: The frequency control of an islanded microgrid is consisted of primary frequency control (PFC) and secondary frequency control (SFC). This paper proposes a novel cooperative application of Battery Energy Storage System (BESS), Photovoltaic (PV) systems and LED lighting loads (LEDLLs) to quickly intercept frequency deviation in the stage of PFC. The slow responding distributed generators handle SFC by restoring the frequency to its nominal value. For participation in PFC, in the case of power shortage, LEDLLs decrease their power consumption, and in the case of power surplus, the PVs decrease their power generation. While PVs and LEDLLs are participating in …PFC with their maximum capability, the BESS frequency controller is tuned to inject/absorb enough power in both cases to keep the frequency within safe limits. In this paper for battery sizing, instead of using its nominal power, a modified overloading capability to fast discharge/charge is used to reduce the required battery size for PFC that also prevents damaging it during fast discharge/charge for PFC. The proposed approach is evaluated on the CIGRE low voltage microgrid using MATLAB/Simulink software. Simulation results show that besides the overloading characteristics, the cooperative utilization of BESS, PVs and LEDLLs also reduce the battery size. Show more

Keywords: Microgrid, Islanded mode, Frequency control, Battery energy storage system, PV, LED lighting loads

DOI: 10.3233/JIFS-200235

Citation: Journal of Intelligent & Fuzzy Systems, vol. 39, no. 3, pp. 4095-4109, 2020