Bipolar Complex Fuzzy Hamacher Aggregation Operators and Their Applications in Multi-Attribute Decision Making

On the basis of Hamacher operations, in this manuscript, we interpret bipolar complex fuzzy Hamacher weighted average (BCFHWA) operator, bipolar complex fuzzy Hamacher ordered weighted average (BCFHOWA) operator, bipolar complex fuzzy Hamacher hybrid average (BCFHHA) operator, bipolar complex fuzzy Hamacher weighted geometric (BCFHWG) operator, bipolar complex fuzzy Hamacher ordered weighted geometric (BCFHOWG) operator, and bipolar complex fuzzy Hamacher hybrid geometric (BCFHHG) operator. We present the features and particular cases of the above-mentioned operators. Subsequently, we use these operators for methods that can resolve bipolar complex fuzzy multiple attribute decision making (MADM) issues. We provide a numerical example to authenticate the interpreted methods. In the end, we compare our approach with existing methods in order to show its effectiveness and practicality.

Ranking the competitiveness of tourist destinations: An analysis using the OWA operator and the SAW method

The objective of this paper is to rank the competitiveness of tourist destinations based on different aggregation operators, specifically, the ordered weighted average (OWA) operator and the simple additive weighting (SAW) method. The use of these methods allows tourist destinations to be sorted according to their competitiveness. In addition, it enables the generation of different scenarios that highlight the relative importance of each criterion. This information is useful for the government and recreation sites when generating different evaluations based on the specific characteristics of each municipality. An application of these methods to determine the competitiveness of the tourism destinations of Sinaloa, Mexico has been performed. JEL Codes: D49, L83, C44 Received: 10/07/2020. Accepted: 03/11/2020. Published: 01/12/2021.

Assessment of Water Availabilities in The Tancítaro Area Through The Fuzzy Willingness To Pay

The Tancítaro peak is located in the State of Michoacán in Mexico. The current situation of unsustainable consumption of water resources can lead the region to a critical situation if adequate measures are not taken. An improvement in water management involving paying for the use of these resources could improve the situation. This work aims to propose a model allowing obtaining an equilibrium price of the use of water in the Tancítaro area. For this, experts will be consulted among the users of the water and experts among those who currently the right to use it, that is, inhabitant of the reserve area. The use of the Fuzzy logic will allow them to express their willingness to pay and collect data, not in a dichotomous way, but by grading their opinions. The use of Ordered Weighted Average (OWA) will allow the aggregation of these opinions bearing in mind different degrees of optimism or pessimism. The results obtained show an equilibrium price of $ 0.49 m-3 . It should be noted that these are preliminary results and the main objective of the work is the presentation of a methodological proposal.

Even More Effort Towards Improved Bounds and Fixed-Parameter Tractability for Multiwinner Rules

Multiwinner elections have proven to be a fruitful research topic with many real world applications. We contribute to this line of research by improving the state of the art regarding the computational complexity of computing good committees. More formally, given a set of candidates C, a set of voters V, each ranking the candidates according to their preferences, and an integer k; a multiwinner voting rule identifies a committee of size k, based on these given voter preferences. In this paper we consider several utilitarian and egailitarian OWA (ordered weighted average) scoring rules, which are an extensively researched family of rules (and a subfamily of the family of committee scoring rules). First, we improve the result of Betzler et al. [JAIR, 2013], which gave a O(n^n) algorithm for computing winner under the Chamberlin Courant rule (CC), where n is the number of voters; to a running time of O(2^n), which is optimal. Furthermore, we study the parameterized complexity of the Pessimist voting rule and describe a few tractable and intractable cases. Apart from such utilitarian voting rules, we extend our study and consider egalitarian median and egalitarian mean (both committee scoring rules), showing some tractable and intractable results, based on nontrivial structural observations.

Reliability allocation of rotary ultrasonic vibration-assisted EDM machine tool based on maximum entropy ordered weighted average and constraint under the index of overall cost

Rotary ultrasonic vibration-assisted EDM is a composite machining method which uses EDM technology to process metal surface and adds rotation and ultrasonic vibration. In this paper, the failure rate of each module of the rotary ultrasonic vibration-assisted EDM machine tool can be accurately predicted by the maximum entropy ordered weighted average algorithm so that the corrected maintenance cost can be predicted. And effective control of preventive maintenance costs can be achieved by selecting the best maintenance times under the premise of reliability. The results showed that the reliability of rotary ultrasonic vibration-assisted EDM machine tool is smoother at non-fixed maintenance intervals by varying the maintenance interval according to the comparison between non-fixed and fixed maintenance cycle. The cost of corrective maintenance can be reduced by varying the measurement to achieve cost optimization in the context of reliability with an optimum number of maintenance cycles and reliability.