Iranian Journal of Fuzzy SystemsIranian Journal of Fuzzy Systems
http://ijfs.usb.ac.ir/
Sat, 29 Apr 2017 11:34:38 +0100FeedCreatorIranian Journal of Fuzzy Systems
http://ijfs.usb.ac.ir/
Feed provided by Iranian Journal of Fuzzy Systems. Click to visit.Cover Vol.14, No.2 April 2017
http://ijfs.usb.ac.ir/article_3139_410.html
Fri, 28 Apr 2017 19:30:00 +0100SOME RESULTS OF MOMENTS OF UNCERTAIN RANDOM VARIABLES
http://ijfs.usb.ac.ir/article_3131_410.html
Chance theory is a mathematical methodology for dealing with indeterminatephenomena including uncertainty and randomness.Consequently, uncertain random variable is developed to describe the phenomena which involveuncertainty and randomness.Thus, uncertain random variable is a fundamental concept in chance theory.This paper provides some practical quantities to describe uncertain random variable.The typical one is the expected value, which is the uncertain version of thecenter of gravity of a physical body.Mathematically, expectations are integrals with respect to chance distributionsor chance measures.In fact, expected values measure the center of gravity of a distribution; they aremeasures of location. In order to describe a distribution in brief terms thereexist additional measures, such as the variance which measures the dispersionor spread, and moments.For calculating the moments of uncertain random variable, some formulas are provided through chance distribution and inverse chance distribution. The main results are explained by using several examples.Fri, 28 Apr 2017 19:30:00 +0100A JOINT DUTY CYCLE SCHEDULING AND ENERGY AWARE ROUTING APPROACH BASED ON EVOLUTIONARY GAME FOR ...
http://ijfs.usb.ac.ir/article_3132_410.html
Network throughput and energy conservation are two conflicting important performance metrics for wireless sensor networks. Since these two objectives are in conflict with each other, it is difficult to achieve them simultaneously. In this paper, a joint duty cycle scheduling and energy aware routing approach is proposed based on evolutionary game theory which is called DREG. Making a trade-off between energy conservation and network throughput, the proposed approach prolongs the network lifetime. The paper is divided into the following sections: Initially, the discussion is presented on how the sensor nodes can be scheduled to sleep or wake up in order to reduce energy consumption in idle listening. The sensor wakeup/sleep scheduling problem with multiple objectives is formulated as an evolutionary game theory. Then, the evolutionary game theory is applied to find an optimal wakeup/sleep scheduling policy, based on a trade-off between network throughput and energy efficiency for each sensor. The evolutionary equilibrium is proposed as a solution for this game. In addition, a routing approach is adopted to propose an energy aware fuzzy logic in order to prolong the network lifetime. The results show that the proposed routing approach balances energy consumption among the sensor nodes in the network, avoiding rapid energy depletion of sensors that have less energy. The proposed simulation study shows the more efficient performance of the proposed system than other methods in term of network lifetime and throughput.Fri, 28 Apr 2017 19:30:00 +0100MULTI-OBJECTIVE ROUTING AND SCHEDULING IN FLEXIBLE MANUFACTURING SYSTEMS UNDER UNCERTAINTY
http://ijfs.usb.ac.ir/article_3133_410.html
The efficiency of transportation system management plays an important role in the planning and operation efficiency of flexible manufacturing systems. Automated Guided Vehicles (AGV) are part of diversified and advanced techniques in the field of material transportation which have many applications today and act as an intermediary between operating and storage equipment and are routed and controlled by an intelligent computer system. In this study, a two-objective mathematical programming model is presented to integrate flow shop scheduling and routing AVGs in a flexible manufacturing system. In real-life problems parameters like demand, due dates and processing times are always uncertain. Therefore, in order to solve a realistic problem, foregoing parameters are considered as fuzzy in our proposed model. Subsequently, to solve fuzzy mathematical programming model, one of the most effective technique in the literature is used. To solve the problem studied, two meta-heuristic algorithms of Non-dominated Sorting Genetic Algorithm-II (NSGAII) and multi-objective particle swarm optimization (MOPSO) are offered that the accuracy of mathematical models and efficiency of algorithms provided are assessed through numerical examples.Fri, 28 Apr 2017 19:30:00 +0100TAUBERIAN THEOREMS FOR THE EULER-NORLUND MEAN-CONVERGENT SEQUENCES OF FUZZY NUMBERS
http://ijfs.usb.ac.ir/article_3134_410.html
Fuzzy set theory has entered into a large variety of disciplines of sciences,technology and humanities having established itself as an extremely versatileinterdisciplinary research area. Accordingly different notions of fuzzystructure have been developed such as fuzzy normed linear space, fuzzytopological vector space, fuzzy sequence space etc. While reviewing theliterature in fuzzy sequence space, we have seen that the notion of Tauberiantheorems for the Euler-N"{o}rlund mean-convergent sequences of fuzzy numbershas not been developed. In the present paper, we introduce some new conceptsabout statistical convergence of sequences of fuzzy numbers. The main purposeof this paper is to study Tauberian theorems for the Euler-N"{o}rlundmean-convergent sequences of fuzzy numbers and investigate some other kind ofconvergences named Euler-N"{o}rlund mean-level convergence so as to fill upthe existing gaps in the literature. The results which we obtained in thisstudy are much more general than those obtained by others.Fri, 28 Apr 2017 19:30:00 +0100ON THE SYSTEM OF LEVEL-ELEMENTS INDUCED BY AN L-SUBSET
http://ijfs.usb.ac.ir/article_3135_410.html
This paper focuses on the relationship between an $L$-subset and the system of level-elements induced by it, where the underlying lattice $L$ is a complete residuated lattice and the domain set of $L$-subset is an $L$-partially ordered set $(X,P)$. Firstly, we obtain the sufficient and necessary condition that an $L$-subset is represented by its system of level-elements. Then, a new representation theorem of intersection-preserving $L$-subsets is shown by using union-preserving system of elements. At last, another representation theorem of compatible intersection-preserving $L$-subsets is obtained by means of compatible union-preserving system of elements.Fri, 28 Apr 2017 19:30:00 +0100FUZZY FRACTIONAL PARTIAL DIFFERENTIAL EQUATIONS IN PARTIALLY ORDERED METRIC SPACES
http://ijfs.usb.ac.ir/article_3136_410.html
In this paper, we consider fuzzy fractional partial differential equations under Caputo generalized Hukuhara differentiability. Some new results on the existence and uniqueness of two types of fuzzy solutions are studied via weakly contractive mapping in the partially ordered metric space. Some application examples are presented to illustrate our main results.Fri, 28 Apr 2017 19:30:00 +0100S-APPROXIMATION SPACES: A FUZZY APPROACH
http://ijfs.usb.ac.ir/article_3137_410.html
In this paper, we study the concept of S-approximation spaces in fuzzy set theory and investigate its properties. Along introducing three pairs of lower and upper approximation operators for fuzzy S-approximation spaces, their properties under different assumptions, e.g. monotonicity and weak complement compatibility are studied. By employing two thresholds for minimum acceptance accuracy and maximum rejection error, these spaces are interpreted in three-way decision systems by defining the corresponding positive, negative and boundary regions.Fri, 28 Apr 2017 19:30:00 +0100FORMAL BALLS IN FUZZY PARTIAL METRIC SPACES
http://ijfs.usb.ac.ir/article_3138_410.html
In this paper, the poset $BX$ of formal balls is studied in fuzzy partial metric space $(X,p,*)$. We introduce the notion of layered complete fuzzy partial metric space and get that the poset $BX$ of formal balls is a dcpo if and only if $(X,p,*)$ is layered complete fuzzy partial metric space.Fri, 28 Apr 2017 19:30:00 +0100Persian-translation vol. 14, no. 2, April 2017
http://ijfs.usb.ac.ir/article_3140_410.html
Fri, 28 Apr 2017 19:30:00 +0100FIXED POINT THEOREMS FOR ORDERED CONTRACTIVE MAPPINGS IN THE WEAK NON-ARCHIMEDEAN FUZZY METRIC ...
http://ijfs.usb.ac.ir/article_2788_0.html
In this paper, the author establishes some fixed point theorems fornonlinear contractive operators in the partially ordered weak non-Archimedeanfuzzy metric spaces. A fuzzy extension theorem of Boyd and Wong's nonlinearcontraction theorem is presented. As a consequence, our main results improvedand generalized some recent coupled fixed point theorems and coincidencepoint theorems.Sat, 09 Dec 2017 20:30:00 +0100ROBUST FUZZY CONTROL DESIGN USING GENETIC ALGORITHM OPTIMIZATION APPROACH: CASE STUDY OF SPARK ...
http://ijfs.usb.ac.ir/article_2790_0.html
In the case of widely-uncertain non-linear system control design,it was very difficult to design a single controller to overcome control designspecifications in all of its dynamical characteristics uncertainties. To resolvethese problems, a new design method of robust fuzzy control proposed. Thesolution offered was by creating multiple soft-switching with Takagi-Sugenofuzzy model for optimal solution control at all operating points that generateuncertainties. Optimal solution control at each operating point was calculatedusing genetic algorithm. A case study of engine torque control of spark ignitionengine model was used to prove this new method of robust fuzzy control design.From the simulation results, it can be concluded that the controller operatesvery well for a wide uncertainty.Sat, 09 Dec 2017 20:30:00 +0100STABILITY OF THE JENSEN'S FUNCTIONAL EQUATION IN MULTI-FUZZY NORMED SPACES
http://ijfs.usb.ac.ir/article_2791_0.html
In this paper, we define the notion of (dual) multi-fuzzy normedspaces and describe some properties of them. We then investigate Ulam-Hyersstability of Jensen’s functional equation for mappings from linear spaces intomulti-fuzzy normed spaces. We establish an asymptotic behavior of the Jensenequation in the framework of multi-fuzzy normed spaces.Sat, 09 Dec 2017 20:30:00 +0100FUZZY PREORDERED SET, FUZZY TOPOLOGY AND FUZZY AUTOMATON BASED ON GENERALIZED RESIDUATED LATTICE
http://ijfs.usb.ac.ir/article_2792_0.html
This work is towards the study of the relationship between fuzzypreordered sets and Alexandrov (left/right) fuzzy topologies based on gener-alized residuated lattices here the fuzzy sets are equipped with generalizedresiduated lattice in which the commutative property doesn't hold. Further,the obtained results are used in the study of fuzzy automata theory.Sat, 09 Dec 2017 20:30:00 +0100GRADED DIUNIFORMITIES
http://ijfs.usb.ac.ir/article_2793_0.html
Graded ditopological texture spaces have been presented and discussedin categorical aspects by Lawrence M. Brown and Alexander Sostakin [7]. In this paper, the authors generalize the structure of diuniformity inditopological texture spaces defined in [13] to the graded ditopological texturespaces and investigate graded ditopologies generated by graded diuniformities.The autors also compare the properties of diuniformities and graded diuniformities.Sat, 09 Dec 2017 20:30:00 +0100M-FUZZIFYING MATROIDS INDUCED BY M-FUZZIFYING CLOSURE OPERATORS
http://ijfs.usb.ac.ir/article_2794_0.html
In this paper, the notion of closure operators of matroids is gen-eralized to fuzzy setting which is called M-fuzzifying closure operators, andsome properties of M-fuzzifying closure operators are discussed. The M-fuzzifying matroid induced by an M-fuzzifying closure operator can induce anM-fuzzifying closure operator. Finally, the characterizations of M-fuzzifyingacyclic matroids are given.Sat, 09 Dec 2017 20:30:00 +0100SELECTIVE GROUPOIDS AND FRAMEWORKS INDUCED BY FUZZY SUBSETS
http://ijfs.usb.ac.ir/article_2795_0.html
In this paper, we show that every selective groupoid induced by afuzzy subset is a pogroupoid, and we discuss several properties in quasi orderedsets by introducing the notion of a framework.Sat, 09 Dec 2017 20:30:00 +0100INFORMATION MEASURES BASED TOPSIS METHOD FOR MULTICRITERIA DECISION MAKING PROBLEM IN ...
http://ijfs.usb.ac.ir/article_2796_0.html
In the fuzzy set theory, information measures play a paramountrole in several areas such as decision making, pattern recognition etc. In thispaper, similarity measure based on cosine function and entropy measures basedon logarithmic function for IFSs are proposed. Comparisons of proposed simi-larity and entropy measures with the existing ones are listed. Numerical resultslimpidly betoken the efficiency of these measures over others. An intuitionisticfuzzy weighted measures (IFWM) with TOPSIS method for multi-criteria de-cision making (MCDM) quandary is introduced to grade the alternatives. Thisapproach is predicated on entropy and weighted similarity measures for IFSs.An authentic case study is discussed to rank the four organizations. To com-pare the different rankings, a portfolio selection problem is considered. Variousportfolios have been constructed and analysed for their risk and return. It hasbeen examined that if the portfolios are developed using the ranking obtainedwith proposed method, the return is increased with slight increment in risk.Sat, 09 Dec 2017 20:30:00 +0100SOME FIXED POINT RESULTS FOR ADMISSIBLE GERAGHTY CONTRACTION TYPE MAPPINGS IN FUZZY METRIC SPACES
http://ijfs.usb.ac.ir/article_2984_0.html
In this paper, we introduce the notions of fuzzy -Geraghty con-traction type mapping and fuzzy -'-contractive mapping and establish someinteresting results on the existence and uniqueness of fixed points for these twotypes of mappings in the setting of fuzzy metric spaces and non-Archimedeanfuzzy metric spaces. The main results of our work generalize and extend someknown comparable results in the literature. Furthermore, several illustrativeexamples are given to support the usability of our obtained results.Fri, 17 Feb 2017 20:30:00 +0100A COMMON FRAMEWORK FOR LATTICE-VALUED, PROBABILISTIC AND APPROACH UNIFORM (CONVERGENCE) SPACES
http://ijfs.usb.ac.ir/article_2985_0.html
We develop a general framework for various lattice-valued, probabilisticand approach uniform convergence spaces. To this end, we use theconcept of s-stratified LM-filter, where L and M are suitable frames. A stratified LMN-uniform convergence tower is then a family of structures indexedby a quantale N. For different choices of L;M and N we obtain the latticevalued,probabilistic and approach uniform convergence spaces as examples.We show that the resulting category sLMN-UCTS is topological, well-fibredand Cartesian closed. We furthermore define stratified LMN-uniform towerspaces and show that the category of these spaces is isomorphic to the subcategoryof stratified LMN-principal uniform convergence tower spaces. Finallywe study the underlying stratified LMN-convergence tower spaces.Fri, 17 Feb 2017 20:30:00 +0100THE CATEGORY OF ⊤-CONVERGENCE SPACES AND ITS CARTESIAN-CLOSEDNESS
http://ijfs.usb.ac.ir/article_2987_0.html
In this paper, we define a kind of lattice-valued convergence spacesbased on the notion of ⊤-filters, namely ⊤-convergence spaces, and show thecategory of ⊤-convergence spaces is Cartesian-closed. Further, in the latticevalued context of a complete MV -algebra, a close relation between the categoryof ⊤-convergence spaces and that of strong L-topological spaces is established.In details, we show that the category of strong L-topological spacesis concretely isomorphic to that of strong L-topological ⊤-convergence spacescategorically and bireflectively embedded in that of ⊤-convergence spaces.Fri, 17 Feb 2017 20:30:00 +0100MULTI CLASS BRAIN TUMOR CLASSIFICATION OF MRI IMAGES USING HYBRID STRUCTURE DESCRIPTOR AND ...
http://ijfs.usb.ac.ir/article_2988_0.html
Medical Image segmentation is to partition the image into a set of regions that are visually obvious and consistent with respect to some properties such as gray level, texture or color. Brain tumor classification is an imperative and difficult task in cancer radiotherapy. The objective of this research is to examine the use of pattern classification methods for distinguishing different types of brain tumors, such as primary gliomas from metastases, and also for grading of gliomas. Manual classification results look better because it involves human intelligence but the disadvantage is that the results may differ from one person to another person and takes long time. MRI image based automatic diagnosis method is used for early diagnosis and treatment of brain tumors. In this article, fully automatic, multi class brain tumor classification approach using hybrid structure descriptor and Fuzzy logic based Pair of RBF kernel support vector machine is developed. The method was applied on a population of 102 brain tumors histologically diagnosed as Meningioma (115), Metastasis (120), Gliomas grade II (65) and Gliomas grade II (70). Classification accuracy of proposed system in class 1(Meningioma) type tumor is 98.6%, class 2 (Metastasis) is 99.29%, class 3(Gliomas grade II) is 97.87% and class 4(Gliomas grade III) is 98.6%.Fri, 17 Feb 2017 20:30:00 +0100BATHTUB HAZARD RATE DISTRIBUTIONS AND FUZZY LIFE TIMES
http://ijfs.usb.ac.ir/article_2989_0.html
The development of life time analysis started back in the $20^{textit{th}}$ century and since then comprehensive developments have been made to model life time data efficiently. Recent development in measurements shows that all continuous measurements can not be measured as precise numbers but they are more or less fuzzy. Life time is also a continuous phenomenon, and has already been shown that life time observations are not precise measurements but fuzzy. Therefore, the corresponding analysis techniques employed on the data require to consider fuzziness of the observations to obtain appropriate estimates.In this study generalized estimators for the parameters and hazard rates are proposed for bathtub failure rate distributions to model fuzzy life time data effectively.Fri, 17 Feb 2017 20:30:00 +0100GENERAL FUZZY AUTOMATA BASED ON COMPLETE RESIDUATED LATTICE-VALUED
http://ijfs.usb.ac.ir/article_2990_0.html
The present paper has been an attempt to investigate the general fuzzy automata on the basis of complete residuated lattice-valued ($L$-GFAs). The study has been chiefly inspired from the work by Mockor cite{15, 16, 17}. Regarding this, the categorical issue of $L$-GFAs has been studied in more details. The main issues addressed in this research include: (1) investigating the relationship between the category of $L$-GFAs and the category of non-deterministic automata (NDAs); as well as the relationship between the category of generalized $L$-GFAs and the category of NDAs; (2) demonstrating the existence of isomorphism between the category of $L$-GFAs and the subcategory of generalized $L$-GFAs and between the category of $L$-GFAs and the category of sets of NDAs; (3) and further scrutinizing some specific relationship between the output $L$-valued subsets of generalized $L$-GFAs and the output $L$-valued of NDAs.Fri, 17 Feb 2017 20:30:00 +0100SOME COMPUTATIONAL RESULTS FOR THE FUZZY RANDOM VALUE OF LIFE ACTUARIAL LIABILITIES
http://ijfs.usb.ac.ir/article_2991_0.html
The concept of fuzzy random variable has been applied in several papers to model the present value of life insurance liabilities. It allows the fuzzy uncertainty of the interest rate and the probabilistic behaviour of mortality to be used throughout the valuation process without any loss of information. Using this framework, and considering a triangular interest rate, this paper develops closed expressions for the expected present value and its defuzzified value, the variance and the distribution function of several well-known actuarial liabilities structures, namely life insurances, endowments and life annuities.Fri, 17 Feb 2017 20:30:00 +0100ARITHMETIC-BASED FUZZY CONTROL
http://ijfs.usb.ac.ir/article_2992_0.html
Fuzzy control is one of the most important parts of fuzzy theory for which several approaches exist. Mamdani uses $alpha$-cuts and builds the union of the membership functions which is called the aggregated consequence function. The resulting function is the starting point of the defuzzification process. In this article, we define a more natural way to calculate the aggregated consequence function via arithmetical operators. Defuzzification is the optimum value of the resultant membership function. The left and right hand sides of the membership function will be handled separately. Here, we present a new ABFC (Arithmetic Based Fuzzy Control) algorithm based on arithmetic operations which use a new defuzzification approach. The solution is much smoother, more accurate, and much faster than the classical Mamdani controller.Fri, 17 Feb 2017 20:30:00 +0100K-FLAT PROJECTIVE FUZZY QUANTALES
http://ijfs.usb.ac.ir/article_3006_0.html
In this paper, we introduce the notion of {bf K}-flatprojective fuzzy quantales, and give an elementary characterizationin terms of a fuzzy binary relation on the fuzzy quantale. Moreover,we prove that {bf K}-flat projective fuzzy quantales are preciselythe coalgebras for a certain comonad on the category of fuzzy quantales. Finally, we present two special cases of {bf K} as examples.Sat, 18 Feb 2017 20:30:00 +0100OPTIMAL LOT-SIZING DECISIONS WITH INTEGRATED PURCHASING, MANUFACTURING AND ASSEMBLING FOR ...
http://ijfs.usb.ac.ir/article_3007_0.html
This work applies fuzzy sets to the integration of purchasing, manufacturing and assembling of production planning decisions with multiple suppliers, multiple components and multiple machines in remanufacturing systems. The developed fuzzy multi-objective linear programming model (FMOLP) simultaneously minimizes total costs, total $text{CO}_2$ emissions and total lead time with reference to customer demand, due date, supplier/manufacturer capacity, lot-size release and machine yield. The proposed FMOLP model provides a recoverable remanufacturing framework that facilitates fuzzy decision-making, enabling the decision maker (DM) to adjust interactively the membership function or parameters during the solution procedure to obtain a preferred and satisfactory solution. To test of the model, it was implemented in various scenarios with a remanufacturing production system. The analytical results in this work can help planner by enabling systematic analysis of the cost-effectiveness of remanufacturing systems and their potential for improving $text{CO}_2$ emissions and lead time in terms of remanufacturing planning. Future investigations may apply the related patterns of non-linear membership functions to develop an actual remanufacturing planning decision.Sat, 18 Feb 2017 20:30:00 +0100DISTINGUISHABILITY AND COMPLETENESS OF CRISP DETERMINISTIC FUZZY AUTOMATA
http://ijfs.usb.ac.ir/article_3008_0.html
In this paper, we introduce and study notions like state-linebreak distinguishability, input-distinguishability and output completeness of states of a crisp deterministic fuzzy automaton. We show that for each crisp deterministic fuzzy automaton there corresponds a unique (up to isomorphism), equivalent distinguished crisp deterministic fuzzy automaton. Finally, we introduce two axioms related to output completeness of states and discuss the interrelationship between them.Sat, 18 Feb 2017 20:30:00 +0100AN OPTIMAL FUZZY SLIDING MODE CONTROLLER DESIGN BASED ON PARTICLE SWARM OPTIMIZATION AND USING ...
http://ijfs.usb.ac.ir/article_3009_0.html
This paper addresses the problems caused by an inappropriate selection of sliding surface parameters in fuzzy sliding mode controllers via an optimization approach. In particular, the proposed method employs the parallel distributed compensator scheme to design the state feedback based control law. The controller gains are determined in offline mode via a linear quadratic regular. The particle swarm optimization is incorporated into the linear quadratic regular technique for determining the optimal weight matrices. Consequently, an optimal sliding surface is obtained using the scalar $sign$ function. This latter is used to design the proposed control law. Finally, the effectiveness of the proposed fuzzy sliding mode controller based on parallel distributed compensator and using particle swarm optimization is evaluated by comparing the obtained results with other reported in literature.Sat, 18 Feb 2017 20:30:00 +0100CERTAIN TYPES OF EDGE m-POLAR FUZZY GRAPHS
http://ijfs.usb.ac.ir/article_3010_0.html
In this research paper, we present a novel frame work for handling $m$-polar information by combining the theory of $m-$polar fuzzy sets with graphs. We introduce certain types of edge regular $m-$polar fuzzy graphs and edge irregular $m-$polar fuzzy graphs. We describe some useful properties of edge regular, strongly edge irregular and strongly edge totally irregular $m-$polar fuzzy graphs. We discuss the relationship between degree of a vertex and degree of an edge in an $m-$polar fuzzy graph. We investigate edge irregularity on a path on $2n$ vertices and barbell graph $B_{n,n}.$ We also present an application of $m-$polar fuzzy graph to decision making.Sat, 18 Feb 2017 20:30:00 +0100STONE DUALITY FOR R0-ALGEBRAS WITH INTERNAL STATES
http://ijfs.usb.ac.ir/article_3011_0.html
$Rsb{0}$-algebras, which were proved to be equivalent to Esteva and Godo's NM-algebras modelled by Fodor's nilpotent minimum t-norm,are the equivalent algebraic semantics of the left-continuous t-norm based fuzzy logic firstly introduced by Guo-jun Wang in the mid 1990s.In this paper, we first establish a Stone duality for the category of MV-skeletons of $Rsb{0}$-algebras and the category of three-valued Stone spaces.Then we extend Flaminio-Montagna internal states to $Rsb{0}$-algebras.Such internal states must be idempotent MV-endomorphisms of $Rsb{0}$-algebras.Lastly we present a Stone duality for the category of MV-skeletons of $Rsb{0}$-algebras with Flaminio-Montagna internal statesand the category of three-valued Stone spaces with Zadeh type idempotent continuous endofunctions.These dualities provide a topological viewpoint for better understanding of the algebraic structures of $Rsb{0}$-algebras.Sat, 18 Feb 2017 20:30:00 +0100INTERVAL-VALUED INTUITIONISTIC FUZZY SETS AND SIMILARITY MEASURE
http://ijfs.usb.ac.ir/article_3012_0.html
In this paper, the problem of measuring the degree of inclusion and similarity measure for two interval-valued intuitionistic fuzzy sets is considered. We propose inclusion and similarity measure by using order on interval-valued intuitionistic fuzzy sets connected with lexicographical order. Moreover, some properties of inclusion and similarity measure and some correlation, between them and aggregations are examined. Finally, we have included example of ranking problem in car showrooms.Sat, 18 Feb 2017 20:30:00 +0100L-FUZZY CONVEXITY INDUCED BY L-CONVEX FUZZY SUBLATTICE DEGREE
http://ijfs.usb.ac.ir/article_3013_0.html
In this paper, the notion of $L$-convex fuzzy sublattices is introduced and their characterizations are given. Furthermore, the notion of the degree to which an $L$-subset is an $L$-convex fuzzy sublattice is proposed and its some characterizations are given. Besides, the $L$-convex fuzzy sublattice degrees of the homomorphic image and pre-image of an $L$-subset are studied. Finally, we obtain an $L$-fuzzy convexity, which is induced by the $L$-convex fuzzy sublattice degrees, in the sense of Shi and Xiu.Sat, 18 Feb 2017 20:30:00 +0100SOME COUPLED FIXED POINT RESULTS ON MODIFIED INTUITIONISTIC FUZZY METRIC SPACES AND APPLICATION ...
http://ijfs.usb.ac.ir/article_3014_0.html
In this paper, we introduce fruitful concepts of common limit range and joint common limit range for coupled mappings on modified intuitionistic fuzzy metric spaces. An illustrations are also given to justify the notion of common limit range and joint common limit range property for coupled maps. The purpose of this paper is to prove fixed point results for coupled mappings on modified intuitionistic fuzzy metric spaces. Moreover, we extend the notion of common limit range property and E.A property for coupled maps on modified intuitionistic fuzzy metric spaces. As an application, we extend our main result to integral type contraction condition and also for finite number of mappings on modified intuitionistic fuzzy metric spaces.Sat, 18 Feb 2017 20:30:00 +0100TIME-VARYING FUZZY SETS BASED ON A GAUSSIAN MEMBERSHIP FUNCTIONS FOR DEVELOPING A FUZZY CONTROLLER
http://ijfs.usb.ac.ir/article_3053_0.html
The paper present a novel type of fuzzy sets, called time-Varying Fuzzy Sets (VFS). These fuzzy sets are based on the Gaussian membership functions, they are depended on the error and they are characterized by the displacement of the kernels to both right and left side of the universe of discourse, the two extremes kernels of the universe are fixed for all time. In this work we focus only on the midpoint movement of the universe, all points of supports (kernels) are shifted by the same distance and in same direction excepted the two extremes points of supports are always fixed for all computation time. To show the effectiveness of this approach we used these VFS to develop a PDC (Parallel Distributed Compensation) fuzzy controller for a nonlinear and certain system in continuous time described by the T-S fuzzy model, the parameters of the functions defining the midpoint movements are optimized by a PSO (Particle Swarm Optimization) approach.Sun, 26 Feb 2017 20:30:00 +0100REDUNDANCY OF MULTISET TOPOLOGICAL SPACES
http://ijfs.usb.ac.ir/article_3054_0.html
In this paper, we show the redundancies of multiset topological spaces. It is proved that $(P^star(U),sqsubseteq)$ and $(Ds(varphi(U)),subseteq)$ are isomorphic. It follows that multiset topological spaces are superfluous and unnecessary in the theoretical view point.Sun, 26 Feb 2017 20:30:00 +0100Fuzzy inclusion linear systems
http://ijfs.usb.ac.ir/article_3055_0.html
In this manuscript, we introduce a new class of fuzzy problems, namely ``fuzzy inclusion linear systems" and propose a fuzzy solution set for it. Then, we present a theoretical discussion about the relationship between the fuzzy solution set of a fuzzy inclusion linear system and the algebraic solution of a fuzzy linear system. New necessary and sufficient conditions are derived for obtaining the unique algebraic solution for a fuzzy linear system. Also, all new concepts are illustrated by numerical examples.Sun, 26 Feb 2017 20:30:00 +0100ADAPTIVE FUZZY OUTPUT FEEDBACK TRACKING CONTROL FOR A CLASS OF NONLINEAR TIME-VARYING DELAY ...
http://ijfs.usb.ac.ir/article_3056_0.html
This paper considers the problem of adaptive output feedback tracking control for a class of nonstrict-feedback nonlinear systems with unknown time-varying delays and unknown backlash-like hysteresis. Fuzzy logic systems are used to estimate the unknown nonlinear functions. Based on the Lyapunov–Krasovskii method, the control scheme is constructed by using the backstepping and adaptive technique. The proposed adaptive controller guarantees that all the closed-loop signals are semiglobally uniformly ultimately bounded and the tracking error can converge to a small neighborhood of the origin. Finally, Simulation results further show the effectiveness of the proposed approach.Sun, 26 Feb 2017 20:30:00 +0100A NOVEL FUZZY-BASED SIMILARITY MEASURE FOR COLLABORATIVE FILTERING TO ALLEVIATE THE SPARSITY PROBLEM
http://ijfs.usb.ac.ir/article_3057_0.html
Memory-based collaborative filtering is the most popular approach to build recommender systems. Despite its success in many applications, it still suffers from several major limitations, including data sparsity. Sparse data affect the quality of the user similarity measurement and consequently the quality of the recommender system. In this paper, we propose a novel user similarity measure based on fuzzy set theory along with default voting technique aimed to provide a valid similarity measurement between users wherever the available ratings are relatively rare. The main idea of this research is to model the rating behaviour of each user by a fuzzy set, and use this model to determine the user's degree of interest on items. Experimental results on the MovieLens and Netflix datasets show the effectiveness of the proposed algorithm in handling data sparsity problem. It also outperforms some state-of-the-art collaborative filtering algorithms in terms of prediction quality.Sun, 26 Feb 2017 20:30:00 +0100FUZZY LOGISTIC DIFFERENCE EQUATION
http://ijfs.usb.ac.ir/article_3066_0.html
In this study, we consider two different inequivalent formulations of the logistic difference equation $x_{n+1}= beta x_n(1- x_n), n=0,1,..., $ where $x_n$ is a sequence of fuzzy numbers and $beta$ is a positive fuzzy number. The major contribution of this paper is to study the existence, uniqueness and global behavior of the solutions for two corresponding equations, using the concept of Hukuhara difference for fuzzy numbers. Finally, some examples are given to illustrate our results.Fri, 03 Mar 2017 20:30:00 +0100TREND-CYCLE ESTIMATION USING FUZZY TRANSFORM OF HIGHER DEGREE
http://ijfs.usb.ac.ir/article_3067_0.html
In this paper, we provide theoretical justification for the application of higher degree fuzzy transform in time series analysis. Under the assumption that a time series can be additively decomposed into a trend-cycle, a seasonal component and a random noise, we demonstrate that the higher degree fuzzy transform technique can be used for the estimation of the trend-cycle, which is one of the basic tasks in time series analysis. We prove that high frequencies appearing in the seasonal component can be arbitrarily suppressed and that random noise, as a stationary process, can be successfully decreased using the fuzzy transform of higher degree with a reasonable adjustment of parameters of a generalized uniform fuzzy partition.Fri, 03 Mar 2017 20:30:00 +0100TOPOLOGICAL SIMILARITY OF L-RELATIONS
http://ijfs.usb.ac.ir/article_3068_0.html
$L$-fuzzy rough sets are extensions of the classical rough sets by relaxing theequivalence relations to $L$-relations. The topological structures induced by$L$-fuzzy rough sets have opened up the way for applications of topological factsand methods in granular computing. In this paper, we firstly prove thateach arbitrary $L$-relation can generate an Alexandrov $L$-topology.Based on this fact, we introduce the topological similarity of $L$-relations,denote it by T-similarity, and we give intuitive characterization ofT-similarity. Then we introduce the variations of a given $L$-relation andinvestigate the relationship among them. Moreover, we prove that each$L$-relation is uniquely topological similar to an $L$-preorder. Finally,we investigate the related algebraic structures of different sets of$L$-relations on the universe.Fri, 03 Mar 2017 20:30:00 +0100TRANSPORT EQUATION WITH FUZZY DATA
http://ijfs.usb.ac.ir/article_3069_0.html
In this paper, we use the generalized differentiability concept tostudy the fuzzy transport equation. We consider transport equationin the homogeneous and non-homogeneous cases with fuzzy initialcondition. We present the solution when speed parameter is a fuzzynumber too. Our method is based on the construction of the solutionsby employing Zadeh's extension principle.Fri, 03 Mar 2017 20:30:00 +0100