Iranian Journal of Fuzzy Systems
Year:2020 | Volume:17 | Issue:6|Papers Count:14

In this paper, we study the existence and uniqueness of solutions to initial value problems associated to ordinary fuzzy differential equations with finite delay in the setting of a generalized Hukuhara derivative. Our approach is based on the results of fixed points of weakly contractive mappings on partially ordered metric spaces.

In this article, we explore some aspects of Fourier analysis on fuzzy sets. In particular, we give a complete characterization of the Fourier coefficients of fuzzy subsets of the unit circle. The main result hinges on a theorem by the Italian mathematician Aldo Ghizzetti. This work was part of a broader project jointly with Professor Vittorio Cafagna, who, sadly, passed away unexpectedly in 2007. His intellectual breadth and inspiring passion for mathematics still keeps shining today.

In this work, we study the joint distribution function as well as the copula of (X-Z; Y ) where the random vector (X; Y; Z) is characterized by a copula CX; Y; Z. We use this copula to analyze a measurement error model. Some theoretical results, several examples as well as a simulation study are proposed for illustration.

In this paper we present construction of new fuzzy measures by applying extended aggregation function on a sequence of fuzzy measures. According to properties of applied aggregation function and properties of initial fuzzy measures, some properties of constructed fuzzy measure are proved. Additionally, one new extended aggregation function named extended weighted arithmetic mean of distorted arguments is introduced, and its relevant properties are proved. It is shown that this extended aggregation function, with appropriated parameters, can be suitable for construction of new fuzzy measures. Other types of non-additive measures can be constructed in the same way, by applying aggregation function on the initial sequence of non-additive measures.

One of the most important problems after natural disasters in every country is the preparation of temporary accom-modations for victims. The developers of preventive plans are also faced with numerous uncertainties in this crisis management topic. Furthermore, uncertainty is not defined in classical mathematical sets. Therefore, the use of intuitionistic fuzzy sets, which include considerations for uncertainty, can be useful in prospective planning in order to counteract possible risks. The main aim of this study is to propose a combined method using risk management and Intuitionistic Fuzzy Analytic Hierarchy Process (IF-AHP) for locating and prioritizing the post-earthquake temporary accommodation sites. To this end, the city of Sanandaj in Iran was selected as the case study of this method. First, brainstorming sessions with 9 crisis management experts from various organizations of Kurdistan province were used to determine 6 decision-making criteria. These criteria were based on identified risks in temporary accommodation process after an earthquake in the region, and criteria extracted from previous studies regarding temporary accommodation locations. The possible alternatives for temporary accommodation sites in this study were 13 different urban public spaces. The pairwise comparison of criteria based on the aim and pairwise comparison of alternative temporary accommodation options based on each criterion was carried out by experts and using intuitionistic fuzzy sets. Finally, the IF-AHP process was used to determine the priority of each alternative.

In this paper, the notions of the linear and g-convex combination for implications which extend the notion of convex combination of fuzzy implications on the unit interval to bounded lattices are introduced. A necessary and sufficient condition for the g-convex combination to be an implication is determined. Some basic properties of the g-convex combinations are discussed. Also, some sets which are defined by the linear (g-convex) combination of two implications on a bounded lattice are studied and the relationships between them are discussed. Moreover, the lattice theoretical structure of the mentioned sets is investigated.

In a construction project, there are many factors that affect the project quality, such as people, materials, machinery, environment, etc. Among them, people have the greatest influence on the project quality, whether people participate directly or indirectly. This paper mainly evaluates human factors in the process of construction project management, such as workers proficiency, workers safety awareness, technical workers quality, and workers emergency capacity, with the purpose of helping Chinas construction project to proceed smoothly. In this manuscript, a multi-attribute group decision-making (MAGDM) technique based on Pythagorean interval 2-tuple linguistic numbers (PI2TLNs) and VIKOR method is proposed to evaluate human factors in construction projects. PI2TLNs are used to represent performance assessments of decision makers. Relying on Pythagorean interval 2-tuple linguistic weighted averaging (PI2TLWA)/Pythagorean interval 2-tuple linguistic weighted geometric (PI2TLWG) operator, the evaluation information given by experts is fused into a group decision matrix. Combined with the essential VIKOR method, PI2TLNVIKOR framework is established. The effectiveness of this method is verified by an example, and compared with two algorithms and PI2TLN-TODIM method.

In this paper, we introduce the complex fuzzy ordered weighted distance (CFOWD) measure. It is a new measure that uses the main characteristics of the the ordered weighted averaging (OWA) operator and uncertain information represented as complex fuzzy values. This measure includes a wide range of distance measures such as the complex fuzzy maximum distance, the complex fuzzy minimum distance, the normalized complex fuzzy distance (NCFD), the complex fuzzy ordered weighted Hamming distance (CFOWHD), complex fuzzy ordered weighted Euclidean distance (CFOWED), complex fuzzy ordered weighted geometric distance (CFOWGD), the normalized complex fuzzy Ham-ming distance (NCFHD) and the normalized complex fuzzy Euclidean distance (NCFED). We study some of its main properties. Finally, based on CFOWD measures, we give an illustrative example regarding the selected problem.

The conventional advanced process yield index ST pk is widely applied in industry to provide an exact measure of the overall production yield whose quality characteristics are mutually independent and multivariate normally distributed. While one can find numerous studies that consider a crisp estimation of ST pk to evaluate and test the overall process yield, the recorded measurements of product quality characteristics are not always reported precisely. This paper presents a new fuzzy-based method to assess the overall process yield in the presence of a specified degree of ambiguity for the sample data. After finding a fuzzy estimator of ST pk based on Buckley's approach, a new fuzzy three-decision testing rule is proposed to evaluate process performance based on critical values and fuzzy p-values. Subsequently, this work extends the application of the proposed method to the class of correlated characteristics by adopting the principal component analysis technique. The introduced fuzzy testing procedure includes the existing customary binary-decision testing rule as a spacial case. In addition, comparative studies are conducted to display the benefits of the proposed rule. Finally, two industrial examples are given for independent and correlated characteristics to guide the practitioners.

In this note, our aim is to present the relation between msets and L-fuzzy sets. We prove that an mset can be viewed as an L-fuzzy set. An mset topology can be viewed as an L-topology. Therefore, it follows that mset topologies are redundant in theoretical sense.

In this paper, the notions of Bosbach states and state-morphisms on implication basic algebra are introduced, along with their properties and related results. It is proved that Bosbach states coincide with Riecan states on bounded implication basic algebras. Accordingly, the relations between Bosbach states and state-morphisms are discussed. It is proved that sm is a state-morphism on IB if and only if sm is a Bosbach state and sm(x _ y) = sm(x) _ sm(y). In addition, the concept of internal states on implication basic algebras is defined, and accordingly, the notions of IS-prefilters, ISfilters, and IS-congruence relations on implication basic algebras are introduced. Then, it is proved that one-to-one correspondence is available between the set of all ISfilters and IS-congruence relations on implication basic algebras. Finally, the new notion of generalized state maps from an implication basic algebra IB1 to an arbitrary implication basic algebra IB2 is defined and generalized state-morphisms and generalized internal states as two types of individual generalized state maps are introduced. This confirmed that the generalized internal states are a generalization of internal states, and the generalized state-morphisms are a generalization of state-morphisms on implication basic algebras. Finally, it is shown that a generalized internal state gs is an internal state on implication basic algebra IB if gs2 = gs.

In this paper, we generalize all of the fuzzy structures which we have discussed in [14] to L-fuzzy set theory, where L =< L;  ; V; W; 0 > denotes a complete distributive lattice with at least two elements. We define the concept of an LG-fuzzy topological space (X; T) which X is itself an L-fuzzy subset of a crisp set M and T is an L-gradation of openness of L-fuzzy subsets of M which are less than or equal to X. Then we define C1 L-fuzzy manifolds with L-gradation of openness and C1 LG-fuzzy mappings of them such as LG-fuzzy immersions and LG-fuzzy imbeddings. We fuzzify the concept of the product manifolds with L-gradation of openness and define LG-fuzzy quotient manifolds when we have an equivalence relation on M and investigate the conditions of the existence of the quotient manifolds. We also introduce LG-fuzzy immersed, imbedded and regular submanifolds.

In this paper, we define and study the modal operators on pseudo-BE algebras as special cases of closure operators on these structures. We prove that the composition of two modal operators is a modal operator if and only if they commute. For the particular case of a good pseudo-BCK algebra an equivalent definition of the modal operators is given, and the notion of a strong modal operator is introduced and studied. We also define the notions of modal deductive systems and modal homomorphisms on pseudo-BE algebras and we investigate their properties. It is proved that, if two modal operators have the same image, then they coincide. Also, given a normal modal deductive system H of a distributive modal pseudo-BE algebra (A; f) we construct a modal operator on the quotient pseudo-BE algebra A=H.

Construction labour productivity is a foremost tool used for data assessing, planning, budgeting and establishment of construction project. Influence of multi variation factors results in decrease of labour productivity in construction field. Still we are dependent on traditional technique comprises with reference published data or on the experience of estimators so as to estimate the construction labour productivity. The objective of this research is to recognize and map the association between identified factors affecting the construction labour productivity and individual productive rates through a systematic engineering model. This process comprises with calculation of productivity, collection of productivity information and using that information for designing construction model. Also, it intends to build up an optimized probabilistic model for construction industry. Initially, the raw data for instance labour cost, capital cost, and energy consumption has been considered as input so as to compute objective function and total productive factor. The membership function is developed and employed in fuzzy optimization algorithm to optimize the productivity rate in construction. The results through anticipated model prove to be more effective model with reasonable generalization capabilities compared to existing traditional work. Furthermore, this paper provides an insight of probabilistic model comprising internal in addition to external variable factors such as supervision, work rules, government rules and public labour unions.