1. Introduction
Real-life problems mainly deal with either imprecise data or the combination of various types of data. Solving such problems with imprecise information is not an easy task. If a problem consists of precise (real number) data, it would be easy to solve such a problem using conventional decision-making algorithms. However, the problem with imprecise information and the problems with incomplete or adequate information cannot be solvable by using various conventional decision-making algorithms. Fuzzy numbers can represent decision-making problems involving imprecise information; hence, they can be solved using various fuzzy decision-making techniques. However, problems with imprecise and incomplete information can be modelled better using intuitionistic fuzzy numbers ([
1,
2,
3]) than fuzzy numbers or real numbers. Further, trapezoidal intuitionistic fuzzy numbers (TrIFNs) were widely used to model problems with imprecise, adequate and qualitative information. Many decision-making algorithms are available to solve these problems modelled under an intuitionistic fuzzy environment. If the problem is modelled using TrIFNs, it is necessary to study the ranking principle to compare arbitrary TrIFNs. The ranking of TrIFNs [
4,
5] plays a vital role in solving problems modelled using trapezoidal intuitionistic fuzzy numbers. Researchers worldwide have introduced various ranking principles for comparing two arbitrary trapezoidal intuitionistic fuzzy numbers. However, none yield a total ordering on the class of trapezoidal intuitionistic fuzzy numbers. In 2016, Nayagam et al. [
6] introduced eight different score functions in the class of TrIFNs and defined a total ordering principle by using those eight score functions. The total ordering principle on the class of TrIFNs makes the decision-making algorithm more efficient. Similarly, the aggregation operators will be used to find the aggregated performance of any alternatives concerning multiple attributes, which plays another important role in any decision-making algorithm. The same decision-making algorithm may give different results based on numerous aggregation operators. Many intuitionistic fuzzy aggregation operators developed, such as the intuitionistic fuzzy weighted averaging operator, intuitionistic fuzzy ordered weighted averaging operator, intuitionistic fuzzy hybrid aggregation operator, Heronian mean, Bonferroni mean, Dombi, trigonometric, Frank and power aggregation operator [
7]. Each of these aggregation operators has its specific purposes, some of which can mitigate the specific influences of irrational data generated by biased decision-makers, such as the power aggregation operator, by allocating the weighted vector based on the degree of support between the input arguments to aggregate the input data and accomplish this purpose. The interrelationship of the aggregated arguments, such as the Heronian mean and Bonferroni mean, can also be considered by certain aggregation operators. In this paper, our main aim is to introduce a new aggregation operator on the set of trapezoidal intuitionistic fuzzy numbers by considering both power aggregation and the Heronian mean operator.
Vojinovic et al. [
8] have developed the novel integrated Improved Fuzzy Stepwise Weight Assessment Ratio Analysis (IMF SWARA) method, Fuzzy Dombi weighted geometric averaging (FDWGA) operator and PESTEL. They have considered five decision-makers for evaluating six main elements of the PESTEL analysis and 30 elements more (five for each group). In total, they have created 35 models based on the developed model. Additionally, the usefulness of the developed integrated model has been demonstrated using a case example.
Riaz et al. [
9] proposed two aggregation operators, namely picture fuzzy hybrid weighted arithmetic geometric aggregation (PFHWAGA) operator and picture fuzzy hybrid ordered weighted arithmetic geometric aggregation (PFHOWAGA) operator, and studied their mathematical properties. The proposed operators outperform the current PFN-defined operators. Further, they have shown the applicability of the proposed aggregation operators by solving an MCDM problem on third-party logistic provider selection. Sahu et al. [
10] proposed two hybridization approaches based on the Hausdorff and Hamming distance measures. They demonstrated two case studies to validate the applicability of the proposed idea.
Zhou et al. [
11] have used the hesitant fuzzy sets (HFSs) to depict the uncertainty in risk evaluation. Then, an improved HFWA (hesitant fuzzy weighted averaging) operator was adopted to fuse the risk evaluation for FMEA experts. Additionally, they have developed the novel HFWGA (hesitant fuzzy weighted geometric averaging) operator. Finally, they have solved a real example of the risk priority evaluation of power transformer parts to show the applicability and feasibility of the proposed hybrid FMEA framework. Ali et al. [
12] have proposed Einstein Geometric Aggregation Operators by using a Novel Complex Interval-valued Pythagorean Fuzzy Setting. They have applied the proposed model for solving the problem in Green Supplier Chain Management. Deveci et al. [
13] proposed a novel extension of CoCoSo with the logarithmic method and the power Heronian function. Additionally, they have applied the proposed model to real-time traffic management problems. Deveci et al. [
14] introduced an Ordinal Priority Approach (OPA) method for determining the criteria weights and application of a fuzzy Dombi Bonferroni (DOBI) methodology for the evaluation of alternatives.
Erdogan et al. [
15] proposed hybrid power Heronian functions in which the linear normalization method is improved by applying the inverse sorting algorithm for rational and objective decision-making. Additionally, they have developed a new multi-criteria decision-making model to determine the best smart charging scheduling that meets electric vehicle (EV) user considerations at the work-places. Jeevaraj [
16] has introduced the idea of interval-valued Fermatean fuzzy sets which is a generalization to many different generalized classes of fuzzy sets [
17] and a total ordering principle on the class of IVFFNs by presenting four different score functions. Pratibha et al. [
18] proposed a new score function for comparing arbitrary interval-valued Fermatean fuzzy numbers. Further, they have introduced a new interval-valued Fermatean fuzzy Einstein aggregation operator to combine various IVFFNs. Finally, an illustrative case study was discussed to assess the performance quality of the developed methodology. In addition, as the complexity of decision-making problems is increasing in the real world, we need to synchronously consider the following conditions in one decision-making problem to choose an optimal alternative. To alleviate these influences, we can select the PA operator to achieve this purpose by assigning the different weights generated by the support measures. We also consider the objective interrelationships between input values in certain cases, and then this function can be completed by the Heronian mean or Bonferroni mean ([
19]). Since HM has some advantages over BM, however, we may expand HM to account for interactions.
The purpose of this paper is, therefore, to combine the PA operator and HM and extend them to trapezoidal intuitionist fuzzy environments and to, propose some of the power Heronian aggregation operators for trapezoidal intuitionistic fuzzy numbers (TrIFNs) and apply them to solve MAGDM problems to meet the two needs as mentioned earlier. The remainder of this paper is shown as follows to do:
We briefly study some basic concepts of the TrIFS, PA operator and HM in
Section 2.
Section 3 suggests some of the power Heronian aggregation operators for TrIFNs and addresses some of these operators’ useful properties and special cases.
We establish a Multi-attribute Group Decision-Making (MAGDM) algorithm in
Section 4 based on the proposed operators.
To illustrate the validity of the proposed method,
Section 5 gives a numerical example.
2. Preliminaries
Some basic definitions are given in this section. Here, we give a brief review of some preliminaries.
Definition 1 (Atanassov, [
20])
. Consider A to be a set that is not empty. An intuitionistic fuzzy set (IFS) in A is represented with , wheresoever and including the constraints . The values and in the range signify the degree of membership and non-membership of a in , correspondingly. The hesitation degree of a to lie in is defined as for any intuitionistic fuzzy subset in A. Definition 2 (Grzegorzewski, [
21])
. In the set of real numbers R, an intuitionistic fuzzy number is described byand is such that , and is the legs of the membership function and the nonmembership function . Non-decreasing continuous functions and , as well as non-increasing continuous functions and , exist.
An intuitionistic fuzzy number with is shown in Figure 1. Definition 3 (Nehi and Maleki, [
22])
. In the set of real numbers ℜ, is an intuitionistic fuzzy set that is trapezoidal type , which holds the conditions. Below is its membership, and non-membership functions are given.The triangular intuitionistic fuzzy numbers are a special case of the trapezoidal intuitionistic fuzzy numbers if in a trapezoidal intuitionistic fuzzy number .
In Figure 2, is an intuitionistic fuzzy set which is a trapezoidal type, which holds the , , , and conditions. We note that the condition of the trapezoidal intuitionistic fuzzy number whose membership and nonmembership fuzzy numbers of are and implies , , , and on the legs of trapezoidal intuitionistic fuzzy number.
Definition 4 (Atanassov & Gargov, [
23])
. Consider to be the set among all closed subintervals of . An interval valued intuitionistic fuzzy set on a set is provided by , where , where is the condition. The and intervals express the degree of belongingness and non-belongingness of the element a to the set , respectively. , and are therefore closed intervals, with , and , denoting the lower and upper end points, respectively. We express wherever .
We can calculate the unknown degree (hesitance degree) of belongingness to as for each element . For simplicity, an intuitionistic fuzzy interval number (IFIN) is indicated as .
Definition 5. Assume , and , and . Below, the TrIFNs operations are listed (Atanassov and Gargov [23], Jun Ye [24]) Definition 6 (Nayagam et al., [
6])
. Consider to be a TrIFN. Then, the membership (L), non-membership (), vague (P), imprecise (), widespread (), complete (), comprehensive (), and exact () score functions for TrIFN are defined as follows: Definition 7 (Nayagam et al., [
6])
. (Ordering principle in the class of TrIFNs). Let and be two TrIFN. A relation ‘Less than’ (‘<’) denoted by on the entire class of TrIFNs is defined as follows:if < then < or
if = and > then < or
if = , = and < then < or
if = , = , = and > then < or
if = , = , = , = and > then < or
if = , = , = , = , = and < then < or
if = , = , = , = , = , = and > then < or
if = , = , = , = , = , = , = and < then < or
if = , = , = , = , = , = , = , = then = .
2.1. The Power Average Operator
The power average (PA), first proposed by Yager [
25], is a useful aggregation operator that can mitigate some of the negative consequences of decision makers’ overly large or small arguments. The classic PA, which is described as follows, may aggregate a collection of crisp integers where the weighting vectors solely depend on the input data.
Definition 8 (Yager [
25])
. Consider to be a set of non-negative real numbers, and the power average (PA) operator is defined aswhereand the support degree for from is . It has the properties listed below. (1) ∈ [0,1]; (2) = ; (3) ≥, if . 2.2. Heronian Mean (HM) Operator
The Heronian mean (HM) is a useful aggregation operator for capturing the interrelationships between the input parameters (Liu and Pei [
26]). It can be defined as follows:
Definition 9 (Liu and Pei [
26])
. Consider I = [0,1], e, f ≥ 0, , if satisfies:The Heronian mean (HM) operator with parameter is therefore defined as .
The HM operator has been shown to have the properties of idempotency, monotonicity, and boundedness (Liu and Pei [26]). 3. The Trapezoidal Intuitionistic Fuzzy Power Heronian Aggregation Operators
According to operation rules defined for TrIFNs, We introduce the trapezoidal intuitionistic fuzzy power Heronian aggregation (TrIFPHA) operator and trapezoidal intuitionistic fuzzy power weighted Heronian aggregation (TrIFPWHA) operator in this section.
Definition 10. Let (where ) be the set of TrIFNs and , and , ifwhere θ is the collection of each TrIFNs, = and . , and the support degree for from is , which consist of the resulting properties. (1) ; (2) ; (3) , if . Therefore, TrIFPHA is called the Trapezoidal intuitionistic fuzzy power Heronian aggregation operator.
The expression (8) can be simplified. For that, we can determineand call a power weighting vector. Certainly, we hold . Thus, The expression (8) can be written as: According to operation rules defined for TrINFS in Equations (1)–(4), Theorem 1’s result is driven as shown below.
Theorem 1. Let (where ) be the set of TrIFNs and . Then, the trapezoidal intuitionistic fuzzy power Heronian aggregation operator (TrIFPHA) obtained by using Equation (10) is a TrIFN, and also Proof. Let
(where
) be the set of TrIFNs and
. By using Equations (1)–(4), we obtain
So,
.
Furthermore, we hold,
Thus, we have
⇒
□
We have to calculate the support degree
to determine the power weighted vector
. Usually, the similarity degree among
and
can equivalently represented as the support degree
. Various similarity measures are available on the class of intuitionistic fuzzy numbers and IVIFNs [
27].
Let us consider two IFNs as . Different similarity measures between the two IFNs are given below.
(1) Chen’s [
28] similarity definition is stated as mentioned below.
(2) Song et al.’s [
29] similarity definition is stated as mentioned below.
(3) Nguyen’s [
30] similarity definition is stated as mentioned below.
where, the knowledge measures of
and
are
and
, each.
The above-mentioned similarity definitions can be extended to TrIFNs using the fuzzy extension principle. Below are the definitions mentioned for them.
Consider
and
be any two trapezoidal fuzzy (intuitionistic type) numbers, thus the definitions are as follows
where, the knowledge measures of
and
are
and
, each.
In this paper, we use a similarity measure between , and for finding .
Further, Some TrIFPHA operator’s properties will be discussed.
Theorem 2 (Idempotency). Let be a collection of TrIFNs, and for each where . Then, .
Proof. From our assumption, we have,
.
(Since is replaced with a similarity measure between and .
Equation (21) and Definition 10 imply that,
Then, from Definition 10, we obtain
Hence the proof. □
Theorem 3 (Boundedness). Let be a set of TrIFNs, and , .
Then, the following condition holds:
Proof. From the Definition 10, we obtain
Likewise, we obtain
Thus,
Likewise, we can also demonstrate that
Therefore, we are able to obtain
□
Though, monotonicity cannot be proven by that.
This is how we can describe it:
Consider and are two sets of TrIFNs. If for each then , and
and
’s support degrees represented as
and
, respectively, and which do not have any inequality relationship among them. This implies that we cannot obtain
and hence it is not possible to obtain
According to the parameter e and f, here we discuss four special cases of the proposed operator ().
(1) A trapezoidal intuitionistic fuzzy power generalized linear descending weighted operator can be generated from Theorem 1 Formula (1) by letting
, and it is shown below.
By Equation (22), we understand that can use a heavy weight vector to measure the information .
(2) A trapezoidal intuitionistic fuzzy power generalized linear ascending weighted operator can be generated from Theorem 1 Formula (1) by letting
, and it is shown below.
By Equation (
23), we understand that
can use a heavy weight vector
to measure the information
.
operator can act as linear weighted function if we consider
or
. Further, we also understand that the parameters
e and
f cannot be substituted for one another according to the Equations (22) and (
23).
(3) A trapezoidal intuitionistic fuzzy power basic Heronian (TrIFPBH) operator can be generated from Theorem 1 Formula (1) by keeping
. The TrIFPBH operator is shown below.