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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 Implementation of MCDM Approaches for a Real-Life Location Selection Problem: A Case Study of Consumer Goods Sector(Springer-Verlag Singapore Pte Ltd., 2022) EMİR, OĞUZSelecting a suitable warehouse location elevates the supply chain performance by reducing the lead times and increasing the response efficiency. Hence, location selection emerges as a strategic decision-making problem for competitive advantage. In this paper, a real decision-making problem of a multinational company operating in the consumer goods sector has been examined. The company's Turkey office is responsible for the operations in many regions such as Middle East, Africa, Central Asia, and Eastern Europe. A case study is handled by the logistics network planning team of the company to evaluate the new warehouse request coming from the regional sales team. For this decision problem, two different multi-criteria decision-making methods TOPSIS and VIKOR, are employed to evaluate four alternative scenarios. In addition, the AHP technique is also applied to determine criteria weights. The results of both methods revealed the same alternative as the best decision.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 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.