Iranian Journal of Fuzzy SystemsIranian Journal of Fuzzy Systems
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Feed provided by Iranian Journal of Fuzzy Systems. Click to visit.(1709-3931) COMPLEX FUZZY Hv-SUBGROUPS OF AN Hv-GROUP
http://ijfs.usb.ac.ir/article_4556_0.html
The concept of complex fuzzy sets is a generalization of ordinaryfuzzy sets. In this paper, we introduce the concept of complex fuzzy subhy-pergroups (Hv-subgroups) as well as the concept of complex anti-fuzzy subhy-pergroups (Hv-subgroups). We investigate their properties and their relationswith the traditional fuzzy (anti-fuzzy) subhypergroups (Hv-subgroups), andwe prove some results in this respect.Mon, 08 Apr 2019 19:30:00 +0100cover Vol.17- No.1 February 2020
http://ijfs.usb.ac.ir/article_5107_698.html
Fri, 31 Jan 2020 20:30:00 +0100Negations and aggregation operators based on a new hesitant fuzzy partial ordering
http://ijfs.usb.ac.ir/article_5106_698.html
Based on a new hesitant fuzzy partial ordering proposed by Garmendia et al.~cite{GaCa:Pohfs}, in this paper a fuzzy disjunction ${D}$ on the set ${H}$ of finite and nonempty subsets of the unit interval and a t-conorm ${S}$ on the set $bar{{B}}$ of equivalence class on the set of finite bags of unit interval based on this partial ordering are introduced respectively. Then, hesitant fuzzy negations $N_n$ on ${H}$ and $mu_n$ on $bar{{B}}$ are proposed. Particularly, their De Morgan's laws are investigated with respect to binary operations ${C}$ and ${D}$ on ${H}$, as well as ${T}$ and {S} on $bar{{B}}$ respectively, where ${C}$ is a commutative fuzzy conjunction on $({H},leq_H)$ and ${T}$ is a t-norm on $(bar{{B}},leq_B)$. Finally, the new hesitant fuzzy aggregation operators are presented on ${H}$ and $bar{{B}}$ and their more general forms are given. Moreover, the validity of the aggregation operations is illustrated by a numerical example on decision making.Fri, 31 Jan 2020 20:30:00 +0100A new method for fuzzification of nested dummy variables by fuzzy clustering membership ...
http://ijfs.usb.ac.ir/article_5108_698.html
In this study, the aim is to propose a new method for fuzzification of nested dummy variables. The fuzzification idea of dummy variables has been acquired from non-linear part of regime switching models in econometrics. In these models, the concept of transfer functions is like the notion of fuzzy membership functions, but no principle or linguistic sentence have been used for inputs. Consequently, for the non-linear part including transfer function, there is no reason why the different types of functions such as logistic are used. Therefore, in order to solve the aforementioned problem like the regime switching models, the transfer functions are considered for dummy variables. However, the presented transfer functions are proposed by fuzzy clustering membership function. Finally, using fuzzy logic, the membership functions of clusters are combined with each other and constitute the fuzzy nested regimes. The suggested model has been used in financial data of Iran's stock in order to examine the equity premium Puzzle. The results of using above model helped in modeling appropriate second-order moments in consumption capital asset pricing model.Fri, 31 Jan 2020 20:30:00 +0100Two-level supply chain for a deteriorating item with stock and promotional cost dependent ...
http://ijfs.usb.ac.ir/article_5109_698.html
In this research work, a wholesaler-retailer-customer supply chain model for a deteriorating item is considered, where the retailer's warehouse in the market place has a limited capacity. The retailer can rent an additional warehouse (rented warehouse) if needed, with a higher rent compared to the existing warehouse (own warehouse). The customers' demand of the item is linearly influenced by the stock level and in case of shortages the base demand is partially backlogged. Being the leader of the supply chain, the retailer introduces some promotional cost to boost the base demand of the item. To participate in joint marketing decision, the wholesaler shares a compromise part of this promotional cost. Goal of this research work is to maximize the individual profits (when the retailer is the leader and the wholesaler is the follower) as well as the channel profit (when the retailer and the wholesaler jointly make marketing decision) of the system. It is established that if the wholesaler shares a part of the promotional cost, then the channel profit as well as the individual profits increase. The supply chain model is also considered in imprecise environment, where different inventory parameters are fuzzy/rough in nature. In this case, the individual profits as well as the channel profit become fuzzy/rough in nature. As optimization of fuzzy/rough objective is not well defined, following credibility/trust measure of fuzzy/rough event, an approach is followed for comparison of fuzzy/rough objectives and a Particle Swarm Optimization algorithm is implemented to find the marketing decisions. Efficiency of the algorithm in solving the problem is statistically established. The existence of the joint marketing decision is established analytically and numerically (with illustration) in crisp as well as in imprecise environments.Fri, 31 Jan 2020 20:30:00 +0100(1807-4621) Super- and sub-additive transformations of aggregation functions from the point of ...
http://ijfs.usb.ac.ir/article_4568_0.html
The way super- and sub-additive transformations of aggregation functions are introduced involve suprema and infimataken over simplexes whose dimensions may grow arbitrarily. Exact values of such transformations may thus be hardto determine in general. In this note we discuss methods of algorithmic approximation of such transformations.Fri, 12 Apr 2019 19:30:00 +0100Degrees of M-fuzzy families of independent L-fuzzy sets
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The present paper studies fuzzy matroids in view of degree. First wegeneralize the notion of $(L,M)$-fuzzy independent structure byintroducing the degree of $M$-fuzzy family of independent $L$-fuzzysets with respect to a mapping from $L^X$ to $M$. Such kind ofdegrees is proved to satisfy some axioms similar to those satisfiedby $(L,M)$-fuzzy independent structure. Then we define and studysome special degrees (e.g. quotient degrees and isomorphism degrees)with respect to mappings between two $(L,M)$-fuzzy matroid-likespaces in details. Finally we give characterizations of thesedegrees and investigate relationships between them.Fri, 31 Jan 2020 20:30:00 +0100Adaptive particularly tunable fuzzy particle swarm optimization algorithm
http://ijfs.usb.ac.ir/article_5111_698.html
Particle Swarm Optimization (PSO) is a metaheuristic optimization algorithm that owes much of its allure to its simplicity and its high effectiveness in solving sophisticated optimization problems. However, since the performance of the standard PSO is prone to being trapped in local extrema, abundant variants of PSO have been proposed by far. For instance, Fuzzy Adaptive PSO (FAPSO) algorithms have been being studied extensively in recent years. In this study, a modified version of PSO algorithms is presented and is named as Adaptive Particularly Tunable Fuzzy Particle Swarm Optimization (APT-FPSO). In it, the global and personal learning coefficients of every single particle are tuned adaptively and particularly, at an individual extent, within each iteration with the aid of fuzzy logic concepts. Ample statistical evidence is provided indicating that the proposed algorithm further improves the potentialities and capabilities of the standard PSO.Fri, 31 Jan 2020 20:30:00 +0100Type-2 fuzzy logic based pitch angle controller for fixed speed wind energy system
http://ijfs.usb.ac.ir/article_5112_698.html
In this paper, an interval Type-2 fuzzy logic based pitch angle controller is proposed for fixed speed wind energy system (WES) to maintain the aerodynamic power at its rated value. The pitch angle reference is generated by the proposed controller which can compensate the non-linear characteristics of the pitch angle to the wind speed. The presence of third dimension in the Type-2 fuzzy logic controller (FLC) membership function offers an additional degree-of-freedom in the design of the Type-2 FLC controller to improve the system performance. The applicability of the proposed controller is evaluated by considering a nonlinear simulation model of the WES which is developed and implemented using OPAL-RT real time digital simulator. The results show that the proposed controller offers better performance than the conventional PI and fuzzy logic controllers.Fri, 31 Jan 2020 20:30:00 +0100A novel ranking method for intuitionistic fuzzy set based on information fusion and application ...
http://ijfs.usb.ac.ir/article_5113_698.html
A novel ranking method based on multi-time information fusion is proposed for intuitionistic fuzzy sets (IFSs) and applied to the threat assessment problem, a multi-attribute decision making (MADM) one. This method integrates a designed intuitionistic fuzzy entropy (IFE), the closeness degree of technique for order preference by similarity to ideal solution (TOPSIS), the decision maker¡¯s (DM¡¯s) risk attitude and decision information from DMs in multiple times. Firstly, a novel IFE is designed in order to sufficiently express the fuzziness and the unknown of uncertainty conveyed by IFSs. Secondly, considering the distance from the positive ideal solution and the negative ideal solution simultaneously, the closeness degree of TOPSIS is utilized to characterize the amount of information conveyed by the IFS. The amount of information and the uncertainty of information are combined by the introduction of DMs¡¯ risk attitudes and then; a novel single time ranking method for IFSs is structured. Next, to reflect the subjective ranking intention on alternatives, the comprehensive preference model of DMs is established. The optimal attribute weights are derived from the linear programming model which incorporates the subjective ranking intension and the objective ranking result. Finally, the decision information from DMs in multiple times is aggregated to give the final ranking results. A threat assessment example and comparison analysis demonstrates the flexibility and effectiveness of the proposed method.Fri, 31 Jan 2020 20:30:00 +0100Customer loyalty program based on quality function deployment with fuzzy linguistic preference ...
http://ijfs.usb.ac.ir/article_5114_698.html
The competition among shopping malls is getting increasingly more intense.In order to enhance corporate competitiveness and profitability, how toretain key loyal customers has become an important issue for the managers ofshopping malls. Customer loyalty programs are a universal practice. Thisstudy proposes an analytical model for developing the strategic managementof customer loyalty programs. Based on quality function deployment, ourmodel constructs a fuzzy relational matrix to integrate the customerbenefits and the customer loyalty programs. The results contribute to abetter understanding of the different importance of customer benefits withrespect to ``Utilitarian benefits'', ``Hedonic benefits'' and ``Symbolicbenefits''. The study's findings provide prioritized customer loyaltyprograms, including ``Newest information transmissions,'' ``Communicationservice specialists,'' ``Exclusive free gift promotions,'' and ``VIP loungeservice,'' which can be used to determine the directions for the improvementof shopping malls. The study has implications for the theory andpractitioners. First, it allows the integration of customer benefits incustomer loyalty programs and the consideration of VIP customers inthe programs. Second, the requirement evaluation considering fuzzylinguistic preferences allows for prioritizing the customer loyalty programswhen dealing with uncertainty and vagueness. Finally, this approach helps toobtain more realistic results by integrating fuzzy decision-making into QFD.Fri, 31 Jan 2020 20:30:00 +0100Generalized interval-valued intuitionistic fuzzy Hamacher generalized Shapley Choquet integral ...
http://ijfs.usb.ac.ir/article_5115_698.html
The interval-valued intuitionistic fuzzy set (IVIFS) which is an extension of the Atanassov’s intuitionistic fuzzy set is a powerful tool for modeling real life decision making problems. In this paper, we propose the emph{generalized interval-valued intuitionistic fuzzy Hamacher generalized Shapley Choquet integral} (GIVIFHGSCI) and the emph{interval-valued intuitionistic fuzzy Hamacher generalized Shapley Choquet integral} (IVIFHGSCI) operators, which consider the importance of the ordered positions and correlations among the arguments with the assumption that the aggregated arguments are interrelated. Furthermore, some of the properties and special cases of these operators are discussed. An approach for multicriteria decision making based on these operators is developed. Finally an illustrative example follows.Fri, 31 Jan 2020 20:30:00 +0100Joint influence of leakage delays and proportional delays on almost periodic solutions for FCNNs
http://ijfs.usb.ac.ir/article_5116_698.html
This paper deals with fuzzy cellular neural networks (FCNNs) with leakage delays and proportional delays. Applying the differential inequality strategy, fixed point theorem and almost periodic function principle, some sufficient criteria which ensure the existence and global attractivity of a unique almost periodic solution for fuzzy cellular neuralnetworks with leakage delays and proportional delays are derived.Computer simulations are carried out to illustrate our theoreticalfindings. Our results are new and complement some previouspublished ones.Fri, 31 Jan 2020 20:30:00 +0100BL-general fuzzy automata and minimal realization: Based on the associated categories
http://ijfs.usb.ac.ir/article_5117_698.html
The present paper is an attempt to study the minimal BL-general fuzzy automata which realizes the given fuzzy behavior. Of two methods applied for construction of such automaton presented here, one has been based on Myhill-Nerode's theory while the other has been based on derivatives of the given fuzzy behavior. Meanwhile, the categories of BL-general fuzzy automata and fuzzy behavior, along with a functorial relationship between them, are introduced.Fri, 31 Jan 2020 20:30:00 +0100The Wijsman structure of a quantale-valued metric space
http://ijfs.usb.ac.ir/article_5118_698.html
We define and study a quantale-valued Wijsman structure on the hyperspace of all non-empty closed sets of a quantale-valued metric space. We show its admissibility and that the metrical coreflection coincides with the quantale-valued Hausdorff metric and that, for a metric space, the topological coreflection coincides with the classical Wijsman topology. We further define an index of compactness and show that the indices of compactness of the quantale-valued metric space and of the hyperspaces equipped with the quantale-valued Hausdorff metric and with the quantale-valued Wijsman structure coincide.Fri, 31 Jan 2020 20:30:00 +0100(1808-4651) The role of states in triangle algebras
http://ijfs.usb.ac.ir/article_4593_0.html
In this paper, we enlarge the language of triangle algebra by adding a unary operation that describes properties of astate. These structure algebras are called state triangle algebra. The vital properties of these algebras are given. Thenotion of state interval-valued residuated lattice (IVRL)-filters are introduced and give some examples and propertiesof them. Using this concept, we define two types IVRL-extended σ-filters of a state triangle algebra.Mon, 15 Apr 2019 19:30:00 +0100On the non-parametric multivariate control charts in fuzzy environment
http://ijfs.usb.ac.ir/article_5119_698.html
Multivariate control chats are generally used in situations where the simultaneous monitoring or control of two or more related quality characteristics is necessary. In most processes in the real world, distribution of the process characteristics are unknown or at least non-normal, so the non-parametric or distribution-free charts are desirable. Most non-parametric statistical process-control techniques depend on ranks. In this survey, we apply the fuzzy set theory to deal with the circumstances thatthe values of each characteristic are presented in linguistic form, so we propose non-parametric multivariate control charts based on sign and Wilcoxon signed-rank tests.The performance of the proposed charts is investigated in a simulation study. Numerical examples are used to demonstrate the effectiveness and performance of the proposed charts.Fri, 31 Jan 2020 20:30:00 +0100Persian-translation - vol.17- no.1 february 2020
http://ijfs.usb.ac.ir/article_5120_698.html
Fri, 31 Jan 2020 20:30:00 +0100(1807-4598) Switching Fuzzy Modelling and Control Scheme Using T-S Fuzzy Systems with Nonlinear ...
http://ijfs.usb.ac.ir/article_4877_0.html
This paper extends the idea of switching T-S fuzzy systems with linear consequent parts to nonlinear ones. Eachnonlinear subsystem is exactly represented by a T-S fuzzy system with Lure type consequent parts, which allows tomodel and control wider classes of switching systems and also reduce the computation burden of control synthesis.With the use of a switching fuzzy Lyapunov function, the LMI conditions for asymptotic stability of the system withmaximum decay-rate and disturbance attenuation properties under arbitrary switching law are derived. Moreover,several numerical examples are provided to demonstrate the effectiveness of the proposed approaches to reduce thecomputational burden of control synthesis and improving the closed-loop performance of the system.Sun, 01 Sep 2019 19:30:00 +0100(1810-4770) Fuzzy Decision Making in Testing Hypotheses: An Introduction to the Packages ...
http://ijfs.usb.ac.ir/article_4878_0.html
This paper reviews and compares two R packages “FPV” and “Fuzzy.p.value”. These packages are designed fortesting hypotheses in a fuzzy environment using a fuzzy p-value based approach. In fact, the packages “FPV” and“Fuzzy.p.value” propose some useful functions for testing hypotheses when the data / hypotheses are fuzzy rather thancrisp. The proposed methods and functions have been presented together with illustrative practical examples.Sun, 01 Sep 2019 19:30:00 +0100(1810-4773) Partially continuous pretopological and topological operators for intuitionistic ...
http://ijfs.usb.ac.ir/article_4879_0.html
In this paper, pretopological and topological operators are introduced based on partially continuous linear transformationsof the membership and non-membership functions for intuitionistic fuzzy sets. They turn out to be a generalizationof the topological operators for intuitionistic fuzzy sets. On the other hand it is a generalization of the fuzzy set pretopologicaloperators introduced by Wenzhong and Kimfung.Sun, 01 Sep 2019 19:30:00 +0100(1903-5072) Continuity of super- and sub-additive transformations of continuous functions
http://ijfs.usb.ac.ir/article_4880_0.html
We prove a continuity inheritance property for super- and sub-additive transformations of non-negative continuousmultivariate functions defined on the domain of all non-negative points and vanishing at the origin. As a corollaryof this result we obtain that super- and sub-additive transformations of continuous aggregation functions are againcontinuous aggregation functions.Sun, 01 Sep 2019 19:30:00 +0100(1812-4922) Ulam-Hyers-Rassias stability for fuzzy fractional integral equations
http://ijfs.usb.ac.ir/article_4895_0.html
In this paper, we study the fuzzy Ulam-Hyers-Rassias stability for two kinds of fuzzy fractional integral equations byemploying the fixed point technique.Sat, 14 Sep 2019 19:30:00 +0100(1904-5145) Probit and nested logit models based on fuzzy measure
http://ijfs.usb.ac.ir/article_4897_0.html
Inspired by the interactive discrete choice logit models [Aggarwal, 2019], this paper presents the advanced familiesof discrete choice models, such as nested logit, mixed logit, and probit models to consider the interaction amongthe attributes. Besides the DM’s attitudinal character is also taken into consideration in the computation of choiceprobabilities. The proposed choice models make use of Choquet integal and the recent attitudinal Choquet integral.The models are termed as Choquet nested logit (CNL), Choquet mixed multinomial logit (CMMNL), and Choquetmultinomial probit (CMP). These are further extended to represent the DM’s attitudinal character, and termed asattitudinal CNL, attitudinal CMMNL, and attitudinal CMP.Sat, 14 Sep 2019 19:30:00 +0100(1808-4632) A new family of (A, N)-implications: construction and properties
http://ijfs.usb.ac.ir/article_4922_0.html
This paper deals with a new family of (A, N)-implications derived from fuzzy negation and continuous monotonefunction, and, some properties, for instance, the left neutrally, the exchange principle, the ordering property, the lawsof contraposition, for the proposed family of (A, N)-implications are studied. Moreover, the T-conditionality and theModus tollens for the new family of (A, N)-implications are also studied and some results are obtained.Fri, 20 Sep 2019 19:30:00 +0100(1811-4847) Single cycle supply chain coordination model for fuzzy stochastic demand of ...
http://ijfs.usb.ac.ir/article_4923_0.html
Market demand of the perishable bakery products are volatile. Hence, demand of such items are random variable.The most appealing demand distribution of such items is lognormal demand distribution. Using historical data, theparameters of lognormal distribution are obtained. But, there is a problem of overestimation or underestimation of theparameters. Fuzzy triangular numbers are used to overcome such problems. Single period (newsboy) inventory model isused to obtain an optimal order quantity. The retailers and manufacturers profit is obtained by using the supply chaincoordination model. At the end of day, all the remaining items rotted. Hence, there is no gain from unsold items. Also,the some items are defective at the time of purchase. Thus, loss sharing strategy is proposed between manufacturersand retailers. All of these aspects are incorporated in the supply chain coordination model. The data is collected fromKoregaon Park, Pune market, India to illustrate the methodology.Fri, 20 Sep 2019 19:30:00 +0100(1810-4760) A fuzzy capacitated facility location-network design model: A hybrid firefly and ...
http://ijfs.usb.ac.ir/article_4924_0.html
Facility location-network design (FLND) problem, which determines the location of facilities and also communicationlinks between the demand and facility nodes, is arisen from the combination of the facility location and network designproblems. This paper deals with fuzzy capacitated facility location-network design model which aims to select thefacilities and candidate links in a way that yield to minimize the total costs, containing: costs of opening facilities, linkconstruction and transportation costs. In this study, several types of links have been considered for connecting twonodes in which their capacity, transportation and construction costs are distinct. Besides, the possibility of multiplelink selection between two nodes and also the necessity of the existence of a facility in some nodes are considered. Thereare also several types of facilities which the budget for each type is unique. Moreover, to open the facilities and toconstruct the links, limited budgets are considered. As a result of the uncertainty in customers demand, an interactivefuzzy solution approach is applied. Because this problem is classified as an NP-hard class, a hybrid meta-heuristicalgorithm based on Firefly and Invasive Weed Optimization (FIWO) is developed. Finally, the behavior of the modelis tested, and the proposed algorithms performance is compared with some other solving methods.Fri, 20 Sep 2019 19:30:00 +0100(1903-5068) Hyperspace of a fuzzy quasi-uniform space
http://ijfs.usb.ac.ir/article_4925_0.html
The aim of this paper is to present a fuzzy counterpart method of constructing the Hausdorff quasi-uniformity of acrisp quasi-uniformity. This process, based on previous works due to Morsi [25] and Georgescu [9], allows to extendprobabilistic and Hutton [0, 1]-quasi-uniformities on a set X to its power set. In this way, we obtain an endofunctor foreach one of the categories of those objects. We will demonstrate the commutativity of these endofunctors with Lowenand Katsaras’ functors. Furthermore, we will prove the compatibility of our construction with the Hausdorff fuzzyquasi-pseudometric introduced in [33].Fri, 20 Sep 2019 19:30:00 +0100(1807-4565) Interval number ranking method considering multiple decision attitudes
http://ijfs.usb.ac.ir/article_4926_0.html
Many interval number ranking methods cannot represent the different attitudes of decision makers with different riskappetites. Therefore, interval numbers are expressed in the Rectangular Coordinate System (RCS). After mining theinterval numbers in the RCS, the Symmetry Axis Compensation Factor, which is known as λ, was introduced, andthe Equivalent Function of the Goal Interval Number (GIN) was deduced. Thus, the interval number ranking methodconsidering symmetry axis compensation was defined along with its application procedures. Additionally, the feasibilityand effectiveness of this method were veried through examples. This method is intuitive and simple and can representmultiple attitudes of decision makers with different risk appetites.Fri, 20 Sep 2019 19:30:00 +0100(1811-4851) Several new results based on the study of distance measures of intuitionistic fuzzy sets
http://ijfs.usb.ac.ir/article_4927_0.html
It is doubtless that intuitionistic fuzzy set (IFS) theory plays an increasingly important role in solving the problemsunder uncertain situation. As one of the most critical members in the theory, distance measure is widely used inmany aspects. Nevertheless, it is a pity that part of the existing distance measures has some drawbacks in practicalsignificance and accuracy. To make up for their drawbacks and pursue more accuracy and effectiveness, in this paper, wepropose a new inclusion relation of IFSs and a new definition called strict distance measure. Based on this new relation,an analysis is given to point out that the common shortcoming of Hamming distance measure and Euclidean distancemeasure is the mishandling of hesitancy degree. Therefore, the role of hesitancy degree in distance measure is studieddeeply and then three strict distance measures are put forward to overcome the above shortcoming. In addition, a noveldefinition called the characteristic function of distance measure is defined to describe the character of strict distancemeasure. On this basis, a theorem is presented to illustrate the inevitability of the occurrence of unrecognized resultin pattern recognition problems in some special cases. This theorem also shows that the problem cannot be entirelyattributed to distance measures. In view of this condition, we provide an appropriate solution. Compared with otherexisting distance measures in some examples, the superiorities of our improved distance measures are demonstrated tobe more effective and more practical significance.Fri, 20 Sep 2019 19:30:00 +0100(1804-4409) A novel ranking method for intuitionistic fuzzy set based on information fusion and ...
http://ijfs.usb.ac.ir/article_4928_0.html
A novel ranking method based on multi-time information fusion is proposed for intuitionistic fuzzy sets (IFSs) andapplied to the threat assessment problem, a multi-attribute decision making (MADM) one. This method integrates adesigned intuitionistic fuzzy entropy (IFE), the closeness degree of technique for order preference by similarity to idealsolution (TOPSIS), the decision maker¡¯s (DM¡¯s) risk attitude and decision information from DMs in multiple times.Firstly, a novel IFE is designed in order to sufficiently express the fuzziness and the unknown of uncertainty conveyed byIFSs. Secondly, considering the distance from the positive ideal solution and the negative ideal solution simultaneously,the closeness degree of TOPSIS is utilized to characterize the amount of information conveyed by the IFS. The amountof information and the uncertainty of information are combined by the introduction of DMs¡¯ risk attitudes and then; anovel single time ranking method for IFSs is structured. Next, to reflect the subjective ranking intention on alternatives,the comprehensive preference model of DMs is established. The optimal attribute weights are derived from the linearprogramming model which incorporates the subjective ranking intension and the objective ranking result. Finally, thedecision information from DMs in multiple times is aggregated to give the final ranking results. A threat assessmentexample and comparison analysis demonstrates the flexibility and effectiveness of the proposed method.Fri, 20 Sep 2019 19:30:00 +0100(1811-4829) Fuzzy based efficient DBS placement in the 5G cellular network
http://ijfs.usb.ac.ir/article_4930_0.html
Currently, cellular networks are one of the essential communication methods for people. Providing proper coverage forthe users and also offering high-quality services to them are two of the most important issues of concern in cellularnetworks. The fifth-generation cellular communication networks can provide higher data transmission rates, which leadto a higher quality of service but this higher rate has let to reduced antenna coverage in these networks. Besides this,natural and unnatural events in the environment can also affect the coverage of users in the cellular network. One wayto resolve this issue is by using drones as cellular antennas. The most important factor in providing good coverageand high-quality service for users is the optimal placement of antennas. In this article, the problem of finding theappropriate locations of drone base stations (DBSs) is modeled as a P-median optimization problem, where P is thenumber of required antennas to cover the users. We have used a fuzzy clustering algorithm to define a set of specifiedcandidate points that are required to select the locations of DBSs in the P-median model. The optimal value of P wasobtained using the bisection algorithm. Finally, the optimal positions of DBSs have been determined by solving theoptimization problem. According to the results, in the case of a proper selection of fuzzy clustering parameters, betterresults will be obtained in comparison to the results of other approaches.Sat, 21 Sep 2019 20:30:00 +0100(1903-5076) Extended and infinite ordered weighted averaging and sum operators with numerical ...
http://ijfs.usb.ac.ir/article_4931_0.html
This study discusses some variants of Ordered Weighted Averaging (OWA) operators and related information aggregationmethods. In detail, we define the Extended Ordered Weighted Sum (EOWS) operator and the Extended OrderedWeighted Averaging (EOWA) operator, which are applied in scientometrics evaluation where the preference is overfinitely many representative works. As contrast, we also define the Infinite Ordered Weighted Sum (InOWS) operatorand the Infinite Ordered Weighted Averaging (InOWA) operator, which are more suitable for the corresponding scientometrics evaluation where all of works of scholars are considered. We also define the family of Infinite Gaussianmaxitive OWA weights function and the family of Infinite Gaussian OWA weights function, and discuss some of theirmathematical properties. Some illustrative examples, comparisons and figures are provided to better expound theirapplicability in scientometrics evaluation.Sat, 21 Sep 2019 20:30:00 +0100(1812-4906) A new quadratic deviation of fuzzy random variable and its application to portfolio ...
http://ijfs.usb.ac.ir/article_4947_0.html
The aim of this paper is to propose a convex risk measure in the framework of fuzzy random theory and verify itsadvantage over the conventional variance approach. For this purpose, this paper defines the quadratic deviation (QD)of fuzzy random variable as the mathematical expectation of QDs of fuzzy variables. As a result, the new risk criterionessentially describes the variation of a fuzzy random variable around its expected value. For triangular and trapezoidalfuzzy random variables as well as their linear combinations, we establish the analytical expressions of their QDs,and obtain the desirable convexity about the analytical expressions with respect to critical parameters. To explorethe practical value of the proposed QD, we apply it to a portfolio selection problem to quantify the investment risk,and develop three mean-QD models to find the optimal allocation of the fund in different risky securities. Due to theconvexity of our QD, the original three mean-QD models can be turned into their equivalent convex parametric quadraticprogramming problems, which can be solved by conventional optimization methods. The computational results clearlydemonstrate that our new QD signicantly reduces the computational complexity that cannot be avoided when varianceis used as a risk criterion. Finally, the numerical comparison between the proposed mean-QD model and mean-variancemodel is conducted to show the consistency between the optimal results in both techniques. Meanwhile, the comparisonbetween the proposed QD, variance, spread, and second moment is made to summarize the similarities and differencesbetween them, distinguish these four risk criteria and determine their respective application scopes in decision systems.Mon, 30 Sep 2019 20:30:00 +0100(1901-4964) New optimality conditions for multiobjective fuzzy programming problems
http://ijfs.usb.ac.ir/article_4964_0.html
In this paper we study fuzzy multiobjective optimization problems defined for n variables. Based on a new p-dimensionalfuzzy stationary-point definition, necessary efficiency conditions are obtained. And we prove that these conditions arealso sufficient under new fuzzy generalized convexity notions. Furthermore, the results are obtained under generaldifferentiability hypothesis.Tue, 15 Oct 2019 20:30:00 +0100(1902-5015) An extended hesitant group decision-making technique based on the prospect theory ...
http://ijfs.usb.ac.ir/article_4989_0.html
Throughout the present manuscript, we are going to introduce a novel group emergency decision-making technique in which the application of prospect theory explains the psychological behaviour of the decision maker who is affected bythe hesitancy and uncertainty of cognition in decision making problems. Instead of usual aggregation procedure, we implement here a new fusion technique that is based on modified version of extended hesitant fuzzy set (EHFS), and itdefinitely keeps possible amount of expert's information more than the existing fusion technique of hesitant fuzzy set (HFS). The main motivation of re-visiting the concept of EHFS comes from its potential role in increasing the richnessof numerical appearance in the form of value-groups, and of course its ability in identifying various decision makers in decision making situations. Such a definition further expands the practical applications of HFSs. Finally, we employthe barrier lake problem to illustrate the feasibility and the validity of the presented technique.Sun, 03 Nov 2019 20:30:00 +0100(1903-5074) Hesitant q-rung orthopair fuzzy aggregation operators with their applications in ...
http://ijfs.usb.ac.ir/article_4990_0.html
The aim of this manuscript is to present a new concept of hesitant q-rung orthopair fuzzy sets (Hq-ROFSs) by combining the concept of the q-ROFSs as well as Hesitant fuzzy sets. The proposed concept is the generalization of the fuzzysets, intuitionistic fuzzy sets, hesitant fuzzy sets, and Pythagorean fuzzy sets as well as intuitionistic hesitant fuzzy sets (IHFSs) and hesitant Pythagorean fuzzy sets (HPFSs).Furthermore some basic operational laws of hesitant q-rungorthopair fuzzy have been investigated. The score and accuracy functions are defined which play a vital role in decision making process for making comparison between the hesitant q-rung orthopair fuzzy numbers (Hq-ROFNs). Underthe Hq-ROF environment, Hq-ROF weighted averaging (Hq-ROFWA) and Hq-ROF weighted geometric (Hq-ROFWG) operators are introduced and various properties of these aggregation operators are studied. Additionaly, a numericalapplication shows that how the proposed operators are utilized to solve multi-criteria decision making (MCDM) problems in which experts added their optimistic and pessimistic preferences. Finally the analysis of proposed method with othermethods is presented which show that the method presented in this paper is more flexible and superior than existing methods.Sun, 03 Nov 2019 20:30:00 +0100(1902-5024) Using Necessarily Weak Efficient Solutions for Solving a Biobjective Transportation ...
http://ijfs.usb.ac.ir/article_4993_0.html
This paper considers a biobjective transportation problem with various fuzzy objective functions coefficients. Fuzzy coefficients can be of different types such as triangular, trapezoidal, (semi) L - R, or flat (semi) L - R fuzzy numbers.First, we convert the problem to a parametric interval biobjective transportation problem using Υ- cuts of fuzzy coefficients. Then, we consider a fix Υ-cut and obtain a necessarily weak efficient solution to the yielded interval biobjectiveprogram by a new algorithm. It uses basic feasible solutions and the parametric simplex algorithm. Furthermore, we suggest another algorithm for finding a reasonable solution, called Υ-necessarily weak efficient, to the main biobjectivetransportation problem. To illustrate the validity and performance of the proposed algorithms, we present some numerical examples. Sun, 03 Nov 2019 20:30:00 +0100(1811-4823) Trend analysis in L-fuzzy contexts with absent values
http://ijfs.usb.ac.ir/article_4994_0.html
Sometimes we have to work with L-fuzzy context sequences where one or more values are missing. These sequences can represent, among other things, the evolution in time of an L-fuzzy context. The studies of tendencies that wehave done so far used tools that are not valid when the L-fuzzy context has unknown values. In this work we address such situations and we propose new methods to tackle the problem. Besides, we use the study of tendencies to analyserelations between the objects and the attributes of L-fuzzy contexts and to replace the absent values taking into account the behaviour of the sequence.Sun, 03 Nov 2019 20:30:00 +0100(1907-5317)The left (right) distributivity of semi-t-operators over 2-uninorms
http://ijfs.usb.ac.ir/article_4997_0.html
Recently the distributive equations involving various classes of aggregation operators have aroused widespread attentionbecause of their importance in the theoretic and applied communities of fuzzy set theory. 2-uninorms and semi-toperators are two special classes of aggregation operators and have been proved to be useful in many areas such asfuzzy decision making, approximate reasoning and so on. Therefore, the aim of this paper is to investigate the left(right) distributivity of semi-t-operators over 2-uninorms. We consider five subclasses of 2-uninorms and characterizethe corresponding left (right) distributive equations of semi-t-operators over 2-uninorms. Thu, 07 Nov 2019 20:30:00 +0100(1810-4789) Power allocation rules under fuzzy behavior and multicriteria situations
http://ijfs.usb.ac.ir/article_5051_0.html
In this paper, we adopt supreme-utilities among fuzzy level (decision) vectors to propose a power allocation rule, itsefficient extension and normalization in the framework of multicriteria fuzzy transferable-utility (TU) games. We alsoprovide several axiomatic results to present the rationality for these rules. Based on different viewpoints, we introducedifferent formulations and dynamic results for the efficient extension and the normalization by applying the reducedgame and the excess function respectively.Fri, 29 Nov 2019 20:30:00 +0100(1903-5053) Product operation and joint interval valued observable
http://ijfs.usb.ac.ir/article_5052_0.html
The aim of this paper is to define the product operation on a family of interval valued events and the notion ofjoint interval valued observable. We show the connection between product operations for interval valued events andintuitionistic fuzzy events, too. We display the relation between joint interval valued observable and joint intuitionisticfuzzy observable. We define a function of several interval valued observables with help of a Borel function and a jointinterval valued observable, too.Fri, 29 Nov 2019 20:30:00 +0100(1906-5269) Interpolating time series based on fuzzy cluster analysis problem
http://ijfs.usb.ac.ir/article_5053_0.html
This study proposes the model for interpolating time series to use them to forecast effectively for future. This model isestablished based on the improved fuzzy clustering analysis problem, which is implemented by the Matlab procedure.The proposed model is illustrated by a data set and tested for many other datasets, especially for 3003 series in M3-Competition data. Comparing to the existing models, the proposed model always gives the best result. We also applythe proposed model in forecasting the salt peak for a coastal province of Vietnam. Examples and applications show thepotential of the studied problem.Fri, 29 Nov 2019 20:30:00 +0100(1904-5152) Fuzzy particle swarm optimization with nearest-better neighborhood for multimodal ...
http://ijfs.usb.ac.ir/article_5054_0.html
In the last decades, many efforts have been made to solve multimodal optimization problems using Particle Swarm Optimization(PSO). To produce good results, these PSO algorithms need to specify some niching parameters to define the local neighborhood. In this paper, our motivation is to propose the novel neighborhood structures that remove undesirableniching parameters without sacrificing performance. Hence, this paper has two main contributions. First, two novel parameter-free neighborhood structures named Topological Nearest-Better (TNB) neighborhood and Distance-basedNearest-Better (DNB) neighborhood are proposed in the topological space and decision space, respectively. Second,two proposed neighborhoods are combined with Fuzzy PSO (FPSO) and two novel niching algorithms, called TNBFPSOand DNB-FPSO, are proposed for solving multimodal optimization problems. It should be noted that we use azero-order fuzzy system to balance between exploration and exploitation in the proposed algorithms. To evaluate theperformance of proposed algorithms, we performed a detailed empirical evaluation on the several standard multimodalbenchmark functions. Our results show that DNB-FPSO statistically outperforms the other compared multimodaloptimization algorithms.Sat, 30 Nov 2019 20:30:00 +0100(1905-5222) Solving Matrix Games with Hesitant Fuzzy Pay-offs
http://ijfs.usb.ac.ir/article_5125_0.html
The objective of this paper is to develop matrix games with pay-offs of triangular hesitant fuzzy elements (THFEs).To solve such games, a new methodology has been derived based on the notion of weighted average operator and scorefunction of THFEs. Firstly, we formulate two non-linear programming problems with THFEs. Then applying thescore function of THFEs, we transform these two problems into two non-linear multi-objective programming problemswith triangular fuzzy numbers (TFNs). Finally, the Lexicographic method is used to solve these two multi-objectiveprogramming problems. A market share problem is considered to show the validity and applicability of the proposedmethodology.Tue, 21 Jan 2020 20:30:00 +0100(1904-5132) General Definitions for the Union and Intersection of Ordered Fuzzy Multisets
http://ijfs.usb.ac.ir/article_5127_0.html
Since its original formulation, the theory of fuzzy sets has spawned a number of extensions where the role of membershipvalues in the real unit interval [0; 1] is handed over to more complex mathematical entities. Amongst the many existingextensions, two similar ones, the fuzzy multisets and the hesitant fuzzy sets, rely on collections of several distinct valuesto represent fuzzy membership, the key difference being that the fuzzy multisets allow for repeated membership valueswhereas the hesitant fuzzy sets do not. But in neither case are these collections of values ordered, as they are simplyrepresented through multisets or sets. In this paper, we study ordered fuzzy multisets, where the membership valuecan be an ordered n-tuple of values, thus accounting for both order and repetition. We present some basic definitionsand results and explore the relation between these ordered fuzzy multisets and the fuzzy multisets and hesitant fuzzysets.Fri, 24 Jan 2020 20:30:00 +0100