Aggregation operators based on interval-valued Fermatean fuzzy linguistic sets for medical waste disposal planning
摘要
This study introduces a novel decision-making framework based on interval-valued Fermatean fuzzy linguistic sets, a new theoretical model designed to capture linguistic uncertainty, interval-valued hesitation, and Fermatean membership characteristics simultaneously. The primary objective is to construct the mathematical foundations of interval-valued Fermatean fuzzy linguistic sets, develop corresponding aggregation operators, propose a new score function, and formulate a complete multi-criteria decision-making algorithm. The research begins by defining interval-valued Fermatean fuzzy linguistic sets and exploring their fundamental algebraic and ordering properties. Several aggregation operators (Weighted Aggregation and Geometric Weighted; Ordered Weighted Average and Ordered Geometric Weighted; Generalized Weighted Averaging and Generalized Weighted Geometric; Generalized Ordered Weighted Averaging and Generalized Ordered Weighted Geometric; and Linguistic Hybrid) tailored to the interval-valued Fermatean fuzzy linguistic structure are proposed, and their properties are rigorously proven. A novel score function is introduced to provide a meaningful ranking mechanism for interval-valued Fermatean fuzzy linguistic evaluations. Building on these components, a new multi-criteria decision-making algorithm is developed. The algorithm is applied to selecting medical waste disposal techniques, a domain characterized by high uncertainty and conflicting criteria. The robustness of the results is examined using the interval-valued Fermatean fuzzy-COPRAS method, and comparative analyses are conducted with previously established fuzzy multi-criteria decision-making approaches. A comprehensive sensitivity analysis is also performed to validate the stability of the proposed framework. The empirical results indicate that the proposed interval-valued Fermatean fuzzy linguistic-based multi-criteria decision-making framework effectively handles linguistic imprecision and interval-valued hesitation, producing reliable and interpretable rankings. For the medical waste disposal problem, the final ranking is obtained as follows: