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Publication Metadata only A novel fuzzy TOPSIS method using emerging interval-valued spherical fuzzy sets(2019-06-03) Kahraman, Cengiz; GÜNDOĞDU, FATMA KUTLUAll the extensions of ordinary fuzzy sets with three-dimensional membership functions such as intuitionistic fuzzy sets, second type intuitionistic fuzzy sets (or Pythagorean fuzzy sets) and neutrosophic sets aim at defining the judgments of decision makers/ experts with a more detailed description. As a new extension of intuitionistic fuzzy sets of second type, the emerging spherical fuzzy sets (SFS) have been proposed by Kutlu Gundogdu and Kahraman (2019b). In spherical fuzzy sets, the sum of membership, non-membership and hesitancy degrees must satisfy the condition0 <= mu(2) + v(2) + pi(2) <= 1 in which these parameters are assigned independently. SFS is an integration of Pythagorean fuzzy sets and neutrosophic sets. In this paper, novel interval-valued spherical fuzzy sets are introduced with their score and accuracy functions; arithmetic and aggregation operations such as interval-valued spherical fuzzy weighted arithmetic mean operator and interval-valued spherical fuzzy geometric mean operator. Later, interval-valued spherical fuzzy sets are employed in developing the extension of TOPSIS under fuzziness. Then, we use the proposed interval-valued spherical fuzzy TOPSIS method in solving a multiple criteria selection problem among 3D printers to verify the developed approach and to demonstrate its practicality and effectiveness. A comparative analysis with single-valued spherical TOPSIS is also performed.Publication Metadata only Spherical fuzzy sets and spherical fuzzy TOPSIS method(Journal of Intelligent Fuzzy Systems, 2019) Cengiz, Kahraman; GÜNDOĞDU, FATMA KUTLU; 273471All the extensions of ordinary fuzzy sets with three dimensional membership functions such as intuitionistic fuzzy sets (IFS), intuitionistic fuzzy sets of second type (IFS2), and neutrosophic fuzzy sets (NFS) aim at defining the judgments of decision makers/ experts with a more detailed description. Introduction of generalized three dimensional spherical fuzzy sets (SFS) including some essential differences from the other fuzzy sets is presented in this paper. The new type of fuzzy sets is based on the spherical fuzzy distances which have been already defined in the literature. Arithmetic operations involving addition, subtraction and multiplication are presented together with their proofs. Aggregation operators, score and accuracy functions are developed. The multi-criteria decision making method TOPSIS is extended to spherical fuzzy TOPSIS and an illustrative example is presented. Additionally, a comparative analysis with intuitionistic fuzzy TOPSIS (IF-TOPSIS) is given.Publication Metadata only A novel VIKOR method using spherical fuzzy sets and its application to warehouse site selection(2019) Kahraman, Cengiz; GÜNDOĞDU, FATMA KUTLUThe extensions of ordinary fuzzy sets such as intuitionistic fuzzy sets (IFS), Pythagorean fuzzy sets (PFS), and neutrosophic sets (NS), whose membership functions are based on three dimensions, aim at collecting experts' judgments more informatively and explicitly. In the literature, generalized three-dimensional spherical fuzzy sets have been developed by Kutlu Gundogdu and Kahraman (2019), including their arithmetic operations, aggregation operators, and defuzzification operations. Spherical Fuzzy Sets (SFS) are a new extension of Intuitionistic, Pythagorean and Neutrosophic Fuzzy sets, a SFS is characterized by a membership degree, a nonmembership degree, and a hesitancy degree satisfying the condition that their squared sum is equal to or less than one. These sets provide a larger preference domain in 3D space for decision makers (DMs). In this paper, our aim is to extend classical VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method to spherical fuzzy VIKOR (SF-VIKOR) method and to show its applicability and validity through an illustrative example and to present a comparative analysis between spherical fuzzy TOPSIS (SF-TOPSIS) and SF-VIKOR. We handle a warehouse location selection problem with four alternatives and four criteria in order to demonstrate the performance of the proposed SF-VIKOR method.Publication Open Access A novel spherical fuzzy analytic hierarchy process and its renewable energy application(2020-03-01) Kutlu Gündoğdu Fatma; Kahraman, CengizThe extensions of ordinary fuzzy sets such as intuitionistic fuzzy sets, Pythagorean fuzzy sets, and neutrosophic sets, whose membership functions are based on three dimensions, aim at collecting experts’ judgments more informatively and explicitly. In the literature, generalized three-dimensional spherical fuzzy sets have been introduced by Kutlu Gündoğdu and Kahraman (J Intell Fuzzy Syst 36(1):337–352, 2019a), including their arithmetic operations, aggregation operators, and defuzzification operations. In this paper, our aim is to extend classical analytic hierarchy process (AHP) to spherical fuzzy AHP (SF-AHP) method and to show its applicability and validity through a renewable energy location selection example and a comparative analysis between neutrosophic AHP and SF-AHP.Publication Metadata only From 1D to 3D Membership:Sphericalfuzzy Sets(2019-09) Kahraman, Cengiz; GÜNDOĞDU, FATMA KUTLU; 273471All the extensions of ordinary fuzzy sets with three dimensional membership functions such as intuitionistic fuzzy sets (IFS), Pythagorean fuzzy sets (PFS), and neutrosophic fuzzy sets (NFS) aim at defining the judgments of decision makers/ experts with a more detailed description. Introduction of generalized three dimensional spherical fuzzy sets including some essential differences from the other fuzzy sets is presented in this paper. The new type of fuzzy sets is based on the spherical relations and arithmetic operations involving addition, subtraction and multiplication are presented together with their proofs. Aggregation operators, score and accuracy functions are developed. The multi-criteria decision making method TOPSIS is extended to spherical fuzzy TOPSIS and an illustrative example is presented. A comparative analysis with intuitionistic fuzzy TOPSIS is also given.Publication Metadata only Spherical fuzzy VIKOR method and Its application to waste management(2019-07) Kahraman, Cengiz; Karaşan, Ali; GÜNDOĞDU, FATMA KUTLU; 273471; 9178; 227871The extensions of ordinary fuzzy sets such as intuitionistic fuzzy sets (IFS). Pythagorean fuzzy sets (PFS). and neutrosopliic sets (NS). whose mem bership functions are based on three dimensions, aim at collecting experts’ judg ments more informatively and explicitly. In the literature, generalized three-di mensional spherical fuzzy sets have been developed by Kutlu Güııdogdu and Kahraman [3]. including their arithmetic operations, aggregation operators, and defuzzfication operations. Spherical Fuzzy Sets (SFS) are a new extension of In tuitionistic. Pythagorean and Neutrosopliic Fuzzy sets. In this paper, our aim is to employ SF-VIKOR method to waste management problems. We handle a waste disposal site selection problem with five alternatives and four criteria in order to demonstrate the performance of the proposed SF-VIKOR method.Publication Metadata only Principals of Spherical Fuzzy Sets(2019-07) GÜNDOĞDU, FATMA KUTLU; 273471The 3D extensions of ordinary fuzzy sets such as intuitionistic fuzzy sets (IFS). Pythagorean fuzzy sets (PFS). and neutrosophic sets (NS) aim to de scribe experts' judgments more informatively and explicitly. Introduction of gen eralized three dimensional spherical frizzy sets (STS) including some essential differences from the other frizzy sets is presented in the literature with their arith metic. aggregation, and defuzzfication operations [6], This study summarizes the previously introduced spherical frizzy sets and as an application spherical frizzy TOPSIS method will be applied to the site selection o f photovoltaic power station.Publication Metadata only Extension of WASPAS with spherical fuzzy sets(2019) Kahraman, Cengiz; GÜNDOĞDU, FATMA KUTLU; 273471; 9178The 3D extensions of ordinary fuzzy sets such as intuitionistic fuzzy sets (IFS), Pythagorean fuzzy sets (PFS), and neutrosophic sets (NS) aim to describe experts’ judgments more informatively and explicitly. In this paper, generalized three dimensional spherical fuzzy sets are presented with their arithmetic, aggregation, and defuzzification operations. Weighted Aggregated Sum Product ASsessment (WASPAS) is a combination of two well-known multi-criteria decision-making (MCDM) methods, which are weighted sum model (WSM) and weighted product model (WPM). The aim of this paper is to extend traditional WASPAS method to spherical fuzzy WASPAS (SF-WASPAS) method and to show its application with an industrial robot selection problem. Additionally, we present comparative and sensitivity analyses to show the validity and robustness of the given decisions.Publication Metadata only Hospital Location Selection Using Spherical Fuzzy TOPSIS(Atlantis Press, 2019) Kahraman, Cengiz; GÜNDOĞDU, FATMA KUTLU; Onar, Sezi Çevik; Öztaysı, BaşarThe three dimensional extensions of ordinary fuzzy sets such as intuitionistic fuzzy sets of type-2 (IFS2) or Pythagorean fuzzy sets (PFS), and neutrosophic sets (NS) aim at collecting experts' judgments more informatively and explicitly. In the literature, generalized three-dimensional spherical fuzzy sets have been introduced by Kutlu Gündoğdu and Kahraman [1]. In this paper, we develop and use spherical fuzzy TOPSIS and apply it to a hospital location selection problem.Publication Metadata only Spherical fuzzy analytic hierarchy process (AHP) and its application to industrial robot selection(2019-07) Kahraman, Cengiz; GÜNDOĞDU, FATMA KUTLU; 273471; 9178The extensions of ordinary fuzzy sets such as intuitionistic fuzzv sets (IFS). Pythagorean fuzzy sets (PFS). and neutrosophic sets (NS). whose mem bership functions are based on three dimensions, aim at collecting experts' judg ments more informatively and explicitly. In the literature, generalized three-di mensional spherical fuzzy sets have been introduced by Kutlu Gündoğdu and Kahraman [2]. including their arithmetic operations, aggregation operators, and defuzzfication operations. In this paper, we develop and use spherical fuzzy’ an alytic hierarchy process (AHP) and apply it to an industrial robot selection problem.