Novel Development to the Theory of Dombi Exponential AggregationOperators inNeutrosophicCubicHesitantFuzzySets: Applications to Solid Waste Disposal Site Selection

Department of Mathematics and Statistics, Hazara University, Mansehra 21130, Pakistan Department of Mathematics, Faculty of Arts and Sciences, Yildiz Technical University, Esenler 34210, Istanbul, Turkey Department of Mathematics and Statistics, International Islamic University, Islamabad, Pakistan Department of Mathematics, Faculty of Science and Arts, Muhayl, Asser, King Khalid University, Saudi Arabia Department of Mathematics and Computer, Faculty of Science, IBB University, IBB, Yemen


Introduction
Decision-making (DM) is one of the crucial problems in real life. Due to population increase and urbanization, the proper disposal of waste is a challenging problem nowadays. e proper disposal of waste is necessary for prevention of viral diseases like typhoid, dengue, and tuberculosis. Aggregation operators are fundamental tools in DM. Different sets and their generalizations like fuzzy set (FS), interval-valued fuzzy set (IVFS), intuitionistic fuzzy set (IFS), hesitant fuzzy set (HFS), neutrosophic set (NS), neutrosophic cubic set (NCS), and several aggregation operators have been defined so far [1][2][3][4]. Different researchers [5][6][7][8] established similarity measures and other important concepts and successfully applied their models to medical diagnosis and selection criteria. Krohling et al. established different useful techniques to sort out MADM problems [9][10][11]. Jun et al. combined IVFS and FS to form a cubic set (CS). e CS is a combination of FS and IVFS. CS has become a vital tool to deal with vague data. Several researchers explored algebraic aspects and apparently defined ideal theory in CS [12][13][14][15]. Smarandache initiated the concept of indeterminacy and described the notion of the neutrosophic set (NS) [16]. NS consist of three independent components, truth, indeterminacy, and falsehood.
is characteristic of NS enables researchers to deal smoothly with inconsistent and vague data. For engineering purposes, the neutrosophic set is strict to [0,1] and is called the single-valued neutrosophic set (SVNS) [17] presented by Wang et al. e NS was further extended to the interval neutrosophic set (INS) [18]. After the appearance of NS, researchers put their contributions to theoretical as well as technological developments of the set [19][20][21][22]. Several researchers use these sets to construct multiattribute decision-making MADM [23][24][25][26][27]. Zhan et al. define aggregation operators and furnished some applications in MADM [28]. Torra defines a hesitant fuzzy set (HFS) [29]. An HFS is basically a function set on X that, when applied to X, returns a subset of [0, 1]. Jun et al. introduced the concept of neutrosophic cubic set (NCS) [30] which consists of both interval-valued neutrosophic and neutrosophic set. ese characteristics of neutrosophic cubic sets make it a powerful tool to deal the vague and inconsistent data more efficiently. Soon after its exploration, it attracted researchers to work in many fields like medicine, algebra, engineering, and decision-making theory. Later, the idea of a cubic hesitant fuzzy set was introduced by Mehmood et al. [31]. Ye [32] proposed the concept of the singlevalued neutrosophic hesitant fuzzy set (SVNHFS) by combining the advantages of the NS and HFS, which permits its membership functions to have sets of possible values, known as truth, indeterminacy, and falsity membership hesitant functions. Liu and Shi [33] proposed hybrid geometric aggregation operators in INHFS and discuss its presentations in MADM. Zhu et al. [34] proposed the method of β-normalization to add some elements to an HFE, which is a useful technique in case of different cardinalities. Lu and Ye [35] introduced exponential laws in single-valued neutrosophic numbers. Later, the exponential aggregation operators were introduced and applied in typhoon disaster evaluation by Tan et al. [36]. Wang and Li proposed some aggregation operators in pictures hesitant fuzzy sets and compared these operators with some existing decisionmaking methods [37,38]. Tan and Zhang introduced trapezoidal fuzzy neutrosophic number arithmetic averaging and hybrid arithmetic averaging for multicriteria decisionmaking [39]. Feng et al. define type-2 hesitant fuzzy sets and explore some important properties of these sets [40]. Turkarslan et al. proposed the similarity measures in fuzzy multiset with application in medical diagnosis [41].
Dombi [42] established a general class of fuzzy operators. e Dombi T-operators are based on an operational parameter, and hence, the operations based on Dombi operators are more flexible than the other algebraic operations. Shi and Ye [43] established Dombi arithmetic and geometric aggregation operators in neutrosophic cubic sets. Liu et al. [44] established Dombi Bonferroni mean operators of intuitionistic fuzzy sets and discuss their applications in MADM problems. Chen and Ye [45] proposed the Dombi weighted aggregation operators in SVNSs and discuss their applications in MADM problems. Bhattacharya et al. [46] proposed the machine learning model-based approach to discussing the demographic influence of risk behavior of urban investors. Biswas et al. [47] establish an ensemble approach for portfolio selection in a multicriteria decisionmaking framework. Shi and Ye [43] proposed Dombi aggregation operators in the neutrosophic cubic environments for MADM. Rehman et al. [48] established neutrosophic cubic hesitant fuzzy geometric aggregation operators for MADM problems. Ashraf et al. [49] proposed interval-valued the picture fuzzy Maclaurin symmetric mean operators for MADM problems. Riaz and Farid [50] established picture fuzzy aggregation approach and applied it to the third-party logistic provider selection process. Several researchers [51][52][53][54], proposed useful techniques and successfully applied their models to solve decision-making problems.
Motivation: the Dombi exponential laws and Dombi exponential aggregation operators are not defined in the intuitionistic fuzzy set, neutrosophic set, and their extensions. e Dombi T-operators are more flexible than the usual T-operators, and exponential operators are an essential family of aggregation operators.
is motivates the researchers to define Dombi exponential aggregation operators so that the inconsistent, hesitant, and vague data can be efficiently handled in the complex work frame where the base is crisp value.
Organization: the rest of this paper is organized as follows: Section 2 deals with some basic definitions used later on. Section 3 discusses Dombi algebraic operational laws and score functions in NCHFSs. In Section 4, we introduced distance and similarity measures in NCHFSs. Exponential operating rules and some useful results in NCHFSs. Section 5 deals with establishing Dombi exponential aggregation operators as NCHFSs. In Section 6, we demonstrate a MADM method based on NCHFDEA operators and use this method in the MADM problem. Section 7 presents the conclusion of the proposed study. e following technique of β-normalization proposed by Zhu et al. is a useful technique in case of different cardinalities of two hesitant fuzzy sets.
Definition 8 (see [42]). e Dombi norms and dual conorms are given, respectively, as where (a, b) ∈ (0, 1) × (0, 1) and δ ∈ R is an operational parameter. Furthermore, the values of D and D * for boundaries are defined as In the next section, first, we define Dombi algebraic operational laws by using Dombi T-norms and T-conorms in NCHFSs. Second, the score functions are defined for the comparison of two NCHFSs.

Dombi Operational Laws in Neutrosophic
Cubic Hesitant Fuzzy Set is a NCHFS.

Complexity
It is very important to discuss the comparison of NCHF values. For comparison of NCHF values, we propose score functions in next section.
Definition 12. Score, accuracy, and certainty. e score, accuracy, and certainty of a NCHF value e score function is a useful tool for ranking the NCHF values. An NCHF value is greater if the interval hesitant and hesitant degrees of truth and indeterminacy membership grades are bigger and the interval hesitant and hesitant degrees of falsity membership grades are smaller. e greater the difference between truth and falsity memberships, the accuracy is higher and the corresponding NCHF value becomes greater. e certainty of an NCHF value depends on the interval hesitant and hesitant degrees of truth membership grades. e bigger the interval between hesitant and hesitant degrees of truth and indeterminacy membership grades, the greater the NCHF value is. e following technique is use for ranking the values. If α � (A, λ), β � (B, μ) be two NCHF values then we say that α ≻ β if and only if S(α) ≻ S(β).
If S(α) � S(β), we compare them on the basis of accuracy. If they have same accuracies too, we define the above comparison on the basis of certainty.
e distances and similarities are important notions in theory of sets. ese two concepts are important tools to describe the degree of closeness in sets. Keeping in mind the importance of these two notions, we define these in the neutrosophic cubic hesitant fuzzy structure.

Distance and Similarity Measures in Neutrosophic Cubic Hesitant Fuzzy Sets
Definition 13. A distance measure is a mapping such that If α � (A, λ), β � (B, μ) are two NCHFS on a set X � x 1 , . . . ., x t , then we define the following.
Normalized Hamming Distance: Normalized Euclidean Distance: Normalized Generalized Distance:  β) is a similarity measure.
Using the above theorem, the similarity measures based on distance measures defined in section 3.5.1 section 3.5.1 are as follows: Remark 1. We can order the NCHF values by using similarity measures as follows: Consider the NCHF values α � (A, λ), β � (B, μ) and corresponding maximum ideal NCHF value Ω � ( If sm(α, Ω) ≻ sm(β, Ω), then α ≻ β, In the next section, we define novel Dombi exponential laws in which bases are crisp values and Table 1
Considering the result to be true for n � m we prove it for n � m+1 as follows: Using (2) and (14), we have □ Complexity

Applications of Neutrosophic Cubic Hesitant Fuzzy Dombi Weighted Exponential Aggregation Operators to MADM Problems
Many methods in MADM ignore the uncertainty and hence yield the results that are unreliable. In this section, we construct algorithm using the Dombi exponential aggregation operators (NCHFDWEs) for MADM problems.
6.1. Solid Waste Disposal Site Selection. Due to population increase and urbanization, the proper disposal of waste is a challenging problem nowadays. e proper disposal of waste is necessary for the prevention of viral diseases like typhoid, dengue, and tuberculosis. Using the above algorithm to select the best alternative (solid waste disposal site) among the given alternatives (sites) K 1 , . . . , K 5 on the basis of attributes (i) F 1 water pollution; (ii) F 2 slope; (iii) F 3 distance from the residential area. e decision matrix D � (d ij ) 5×3 , where entry d ij represents the preference of alternative K i (i � 1, . . . , 5) corresponding to attribute F j (j � 1, 2, 3), is constructed using fuzzy values with the help of the following scale.
e weights of the attributes are given as Scores S(d i )are given using equation (5).
Similarity measures sm G (d i ) are given using (10) and (12). Figure 1 is the graphical representation of score and similarity measures of aggregated values obtained in Table 2.
Aggregated values of alternatives using the NCHFDWE operators (equation (15) Scores S(d i ) are given using equation (5): Similarity measures sm G (d i ) are given using (10) and (12). Figure 2 is the graphical representation of score and similarity measures of aggregated values obtained in Table 3.
Aggregated values of alternatives using NCHFDWE operators (equation (15)) with σ � 3: Step 1: Identification of alternatives and attributes. Let K 1 , K 2 , . . . , K r , be the set of r alternatives, F 1 , F 2 , . . . , F s be s attributes. e NCHFS α j is used as weight for the attribute F j . A decision matrix is D � (d ij ) consisting fuzzy values, where d ij represent the preference of alternative K i corresponding to attribute F j .
Step 2. Allocation of weights to attributes e NCHF value α j is used as weight assigned to attribute F j .
Step 4. Ranking of Alternatives We calculate the scores and similarity measures S(d j ), sm(d j , Ω); j � 1, . . . , r of the alternatives K j ; i � 1, . . . , r using equations (5), (10) and (14). Using scores and similarity measures, we rank the alternatives K i ; i � 1, . . . , n. If scores of two alternatives are equal, then, we use accuracy function for ranking and if they have same accuracy, we use certainty. ALGORITHM 1: Algorithm using the dombi exponential aggregation operators (NCHFDWE) for MADM problems.
Scores S(d i ) are given using equation (5) Similarity measures sm G (d i ) are given using (10) and (12): Figure 3 is the graphical representation of score and similarity measures of aggregated values obtained in Table 4.
It can be seen from Figures 1-3, that we obtain the same ranking with respect to different choices of parameters q and σ. Hence the most desirable alternative is K 2 .

Comparative Analysis.
To check the validity of results, the above problem is solved by different existing techniques proposed in [36,46]. e results obtained by these existing methods are similar to those obtained from this study in Tables 2-4.

Conclusion
First, the Dombi algebraic operations distance and similarity measures in neutrosophic cubic hesitant fuzzy sets are defined. en the properties of these notions are discussed. Furthermore, the novel Dombi exponential laws and Dombi exponential aggregation operators are proposed. e Dombi exponential laws are more flexible than the usual exponential laws as they involve an operational parameter. Using these aggregation operators, we established a MADM method. e proper disposal of waste is necessary for the prevention of viral diseases like typhoid, dengue, and tuberculosis. e solid waste disposal site selection problem is solved using the proposed MADM method. To discuss the effectiveness of the  proposed method, different values of parameters are considered to check the efficiency of the proposed method. At last, the comparative analysis is presented for validation of proposed operators and methods. For further research, the neutrosophic cubic hesitant fuzzy Dombi arithmetic and geometric aggregation operators and multiexpert decision-making methods using these aggregation operators will be developed. e Dombi Bonferroni mean operators of neutrosophic cubic hesitant fuzzy sets will be established. e Dombi exponential laws and Dombi exponential aggregation operators for Pythagorean fuzzy sets and picture hesitant fuzzy sets will be established [51][52][53][54][56][57][58][59][60].

Limitations of the Proposed Study. As Dombi operations
and generalized similarity measures involve operational parameters, the manual calculation is very complicated and time-consuming. Hence there is a need to develop a software program for such computations. Furthermore, for MADM problems involving more alternatives and attributes handled by Dombi exponential aggregation operators, software programming is needed. We are trying to develop such programming using PYTHON.

Data Availability
No data were used to support the study.

Conflicts of Interest
e authors declare that they have no conflicts of interest.