** Supplier Evaluation in Green Supply Chain: An Adaptive Weight D-S Theory Model Based on Fuzzy-Rough-Sets-AHP Method **

Lianhui Li* , Guanying Xu* and Hongguang Wang**

## Article Information

## Abstract

**Abstract:** Supplier evaluation is of great significance in green supply chain management. Influenced by factors such as economic globalization, sustainable development, a holistic index framework is difficult to establish in green supply chain. Furthermore, the initial index values of candidate suppliers are often characterized by uncertainty and incompleteness and the index weight is variable. To solve these problems, an index framework is established after comprehensive consideration of the major factors. Then an adaptive weight D-S theory model is put forward, and a fuzzy-rough-sets-AHP method is proposed to solve the adaptive weight in the index framework. The case study and the comparison with TOPSIS show that the adaptive weight D-S theory model in this paper is feasible and effective.

**Keywords:** Adaptive Weight , D-S Theory , Fuzzy-Rough-Sets-AHP , Green Supply Chain , Supplier Evaluation

## 1. Introduction

With the fast growth of economic globalization, the resources and environment are facing enormous pressure now. Under this background, green supply chain management (GSCM) appears very important [1]. Green supply chain (GSC) was put forward in 1996 by the Manufacturing Research Center (MRC) of Michigan State University in a research on environmentally responsible manufacturing [2,3]. GSCM contains many contents, such as green supplier evaluation (GSE), green product design (GPD), green production (GP), green marketing and waste recycling (GMWR). As the upstream in the whole supply chain, the role of supplier in protecting the environment and saving costs can be transmitted to every part of the downstream through the supply chain, so as to improve the compatibility of supply chain and environment [4]. Manufacturing enterprises begin to measure the green degree of their suppliers, and one of the key steps to measure the green degree of an enterprise is how to choose the best supplier as a long-term partner [5]. By choosing the suitable green supplier, enterprises can largely improve the resource recycling rate and reduce pollutant emissions, and provide green control and processing for raw materials supplied by suppliers. Thus, the whole supply chain will be green, and a green strategic partnership is established with the supplier to achieve sustainable development. In general, one of the keys to building a green supply chain is to choose a suitable supplier.

The rest of this paper is organized as follows. In Section 2, an overview of the existing researches on supplier evaluation in GSC is provided. In Section 3, an adaptive weight D-S evidence theory model based on fuzzy-rough-sets-AHP method is put forward for supplier evaluation in GSC. In Section 4, a bearing cage supplier evaluation case is given. At last, this paper is concluded in Section 5.

## 2. Literature Review

A lot of significant studies on supplier evaluation in GSC are seen in the existing literatures. The representative research mainly focuses on two aspects as follows.

One is application of single method to the supplier evaluation problem. Buyukozkan and Cifci [6] proposed a fuzzy analytic network process (ANP) method based on multi-person decision-making schema under incomplete preference relationships for vendor selection. Based on the application of rough set theory to study the relations among organizational properties, supplier development program involvement properties, and performance outcome properties, Bai and Sarkis [7] put forward a formal model for green supplier selection. Tseng and Chiu [8] determined the weights of criteria and alternatives according to both by qualitative and quantitative information and sorted alternative suppliers based on a grey relational analysis (GRA). To obtain the best green supplier for a plastic manufacturing company in Singapore, Kannan et al. [9] put forward a fuzzy axiomatic design (FAD) method. To evaluate environmental performance of suppliers, Awasthi et al. [[10] proposed a fuzzy multi-criteria method (FmCM). By adding green criteria into the criteria framework of supplier selection, Yeh and Chuang [11] proposed an optimum mathematical planning model (OMPM) for green partner selection. Wu et al. [12] proposed a fuzzy linguistic decision-making method to solve the problem of selecting green supplier.

The other is integrated application of two or more than two methods for supplier evaluation. Li and Zhao [13] built the assessment model by using threshold method and gray correlation analysis (GCA) for vehicle component supplier selecting. Yan [14] used genetic algorithm (GA) and AHP to realize the dynamic adjustment of index weights in green supplier selection. Kuo et al. [15] proposed a hybrid approach based on artificial neural network (ANN), data envelopment analysis (DEA), and ANP for green supplier selection. Kuo and Lin [16] put forward a supplier selection approach based on ANP and DEA with the consideration of green indicators due to environmental protection issues. Based on fuzzy decision-making trial and evaluation laboratory model (DEMATEL), ANP, and technique for order performance by similarity to ideal solution (TOPSIS), Buyukozkan and Cifci [17] proposed a hybrid fuzzy multi-criteria decision-making (MCDM) approach for green supplier evaluation. By combining AHP and TOPSIS, Luo and Peng [18] proposed an integrated model for both of evaluation and selection of green supplier.

The above two kinds of methods have theoretical basis and practical value, but they also have some limitations. The subjectivity of fuzzy AHP in determining the index weight is too large. Neural network calculation process is complex, redundant, which will result in lack of accurate calculation. TOPSIS method has the advantages of convenient calculation and strong applicability, but the evaluation process may be missing information and the results are not objective enough. Additionally, each evaluation expert is required to give personal subjective evaluation information when considering the same evaluation index set. When different evaluation experts compare multiple indicators on the same level, it is easy to appear contradictory or chaotic judgment and evaluation. Because of the limitations of evaluation experts’ understanding of supplier capabilities, the evaluation index value is often characterized by uncertainty and incompleteness. Moreover, the evaluation index weight is obviously variable when the demand has changed or the preference of the evaluation experts is different.

Therefore, we proposed an adaptive weight D-S theory model in this paper to solve the uncertainty and incompleteness problems of index value of supplier evaluation in GSC. The adaptive weight of evaluation index is determined by our designed fuzzy-rough-sets-AHP method.

## 3. Adaptive Weight D-S Theory Model for Supplier Evaluation

##### 3.1 Establishment of Index Framework

For supplier evaluation in green supply chain, to build a comprehensive index framework is of great significance. On the one hand, product attribute is the main ability embodiment of a supplier; on the other, comprehensive ability can give a strong support to the product attribute of a supplier. Here, the comprehensive ability mainly contains internal competitiveness, external competitiveness, and cooperation ability.

For internal competitiveness, it mainly can be divided into innovation ability, manufacturing capacity and agility. Because a supplier is not isolated in supply chain, it is unavoidably limited by its external competitiveness. For external competitiveness, it mainly can be divided into economic environment, geographical environment, social environment, and legal environment. For cooperation ability, it mainly can be divided into technical compatibility degree, cultural compatibility degree, information platform compatibility degree and reputation.

Therefore, the index framework of supplier evaluation in GSC is built as shown in Fig. 1. It can be represented as a criterion set {C_{1}, C_{2},C_{3},C_{4}}. Here, C_{1} stands for product attribute, C_{2} stands for internal competitiveness, C_{3} stands for external competitiveness, and C_{4} stands for cooperation ability. Among them, C_{1}={C_{11}, C_{12}, C_{13}, C_{14}}. In other words, C1 is divided into four indexes: C_{11}, C_{12}, C_{13}, and C_{14}. Here, C_{11} stands for cost, C_{12}stands for quality, C_{13} stands for service, and C_{14} stands for flexibility.

Four criterions are divided into two types as follows. (1) Comprehensive qualitative type: C_{1}.(2) Quantitative type: C_{2}, C_{3}, and C_{4}. For comprehensive qualitative type criterion, its value is determined by its subordinate indexes. For quantitative type criterion, its value is obtained by expert score method. Similarly, four indexes of C_{1} are divided into two types as follows. (1) Quantitative type: C_{11} and C_{12}. (2) Direct qualitative type: C_{13} and C_{14}.

##### 3.2 Determination of the Adaptive Weight

The AHP method [19], which was put forward by Thomas L. Saaty, can not only make clear the hierarchical structure of the components of complex problem, but also verify the consistency of the results. Therefore, it has been widely applied in the weighting of multi-attribute decision-making problem [20-22]. The traditional AHP uses exact numbers to represent the relative importance between indexes. The evaluation of relative importance between indexes in supplier evaluation by experts depends on personal judgment and subjective experience, so using exact numbers to represent the relative importance between indexes is unjustified to some extent.

Fuzzy number can give expression to the connatural uncertainty of expert's preference. Additionally, the evaluation of relative importance between indexes by multiple experts is obviously indistinguishable when integrating the opinions of all experts. Instead of a membership function, rough boundary interval [21,23] can represent the indistinguishability as a set boundary area. It can better integrate the opinions of all evaluation experts. Accordingly, a fuzzy-rough-sets-AHP method is designed to solve the adaptive weight of evaluation index.

We use U to represent a domain which is actually a nonempty finite set of objects. Y is any object in U. In U, all objects are divided into n partitions: S_{1},S_{2},…,S_{n}. If these n partition has the order of [TeX:] $$S_{1}<S_{2}<\ldots<S_{n}$$, the upper and lower approximation sets of any partition S_{i} (1≤i≤n) can be defined as follows:

##### (1)

[TeX:] $$\begin{array}{l}{\overline{A S}\left(S_{i}\right)=\left\{Y \in K | K \subseteq U / R(Y) \wedge K \geq S_{i}\right\}} \\ {\underline{A S}\left(S_{i}\right)=\left\{Y \in K | K \subseteq U / R(Y) \wedge K \leq S_{i}\right\}}\end{array}$$where U/R(Y) represents the partition of the indistinct relationship R(Y) in U.

According to the above definition, any ambiguous partition S_{i} in U can be represented by its rough boundary interval RN(S_{i}). RN(S_{i}) consists of its rough lower limit [TeX:] $$\underline{L}\left(S_{i}\right)$$ and rough upper limit [TeX:] $$\overline{L}\left(S_{i}\right)$$ which are defined as follows:

##### (2)

[TeX:] $$\underline{L}\left(S_{i}\right)=\frac{\sum_{Y \in A S\left(S_{i}\right)} R(Y)}{\underline{N}\left(S_{i}\right)}$$

##### (3)

[TeX:] $$\overline{L}\left(S_{i}\right)=\frac{\sum_{Y \in A S\left(S_{i}\right)} R(Y)}{\overline{N}\left(S_{i}\right)}$$ where [TeX:] $$\underline{N}\left(S_{i}\right)$$ is the number of objects in the upper approximation set of Si and [TeX:] $$\underline{N}\left(S_{i}\right)$$ is the number of objects in the upper approximation set of S_{i}.

As can be seen, an ambiguous partition in the domain can be represented by a rough boundary interval containing a rough lower limit and a rough upper limit as follows:

##### (4)

[TeX:] $$R N\left(S_{i}\right)=\left[\underline{L}\left(S_{i}\right), \overline{L}\left(S_{i}\right)\right]$$We start from the bottom layer of index framework shown in Fig. 1. There are q experts. The index set is [TeX:] $$\left\{C_{11}, C_{12}, \ldots, C_{1 l}\right\} . \text { Here }, l=4$$

**Step 1:** According to the evaluation of expert [TeX:] $$k(k=1,2, \ldots, q) \text { on }\left\{C_{11}, C_{12}, \ldots, C_{1 l}\right\}$$, the fuzzy reciprocal judgment matrix E^{k} is constructed as follows:

##### (5)

[TeX:] $$E^{k}=\left[\begin{array}{cccc}{(1,1,1,1)} & {e_{1,2}^{k}} & {\cdots} & {e_{1, l}^{k}} \\ {e_{2,1}^{k}} & {(1,1,1,1)} & {\cdots} & {e_{2, l}^{k}} \\ {\vdots} & {\vdots} & {} & {\vdots} \\ {e_{l, 1}^{k}} & {e_{l, 2}^{k}} & {\cdots} & {(1,1,1,1)}\end{array}\right]$$ where [TeX:] $$e_{i j}^{k}$$ represents the score of supplier j compared to supplier i evaluated by expert k, here i,j=1,2,...,l and [TeX:] $$i \neq j . \quad e_{i, j}^{k}=\left(a_{i, j}^{k}, b_{i, j}^{k}, c_{i, j}^{k}, d_{i, j}^{k}\right)$$ is a trapezoidal fuzzy number and [TeX:] $$a_{i, j}^{k}, b_{i, j}^{k}, c_{i, j}^{k} \quad \text { and } \quad d_{i, j}^{k}$$ [TeX:] $$\left(a_{i, j}^{k} \leq b_{i, j}^{k} \leq c_{i, j}^{k} \leq d_{i, j}^{k}\right)$$ are all positive real numbers. Then we verify the consistency of E^{k}. If it is qualified, do the next step; otherwise, redo this step.

**Step 2:** E^{k} is split into a^{k}, b^{k}, c^{k}, d^{k}. The expression of a^{k} is as follows:

##### (6)

[TeX:] $$a^{k}=\left[\begin{array}{cccc}{1} & {a_{1,2}^{k}} & {\cdots} & {a_{1, l}^{k}} \\ {a_{2,1}^{k}} & {1} & {\cdots} & {a_{2, l}^{k}} \\ {\vdots} & {\vdots} & {} & {\vdots} \\ {a_{l, 1}^{k}} & {a_{l, 2}^{k}} & {\cdots} & {1}\end{array}\right]$$ **Step 3:** Based on a^{1},a^{2},…, a^{q}, the rough group decision matrix is constructed as follows:

##### (7)

[TeX:] $$a=\left[\begin{array}{cccc}{1} & {a_{1,2}} & {\cdots} & {a_{1, l}} \\ {a_{2,1}} & {1} & {\cdots} & {a_{2, l}} \\ {\vdots} & {\vdots} & {} & {\vdots} \\ {a_{l, 1}} & {a_{l, 2}} & {\cdots} & {1}\end{array}\right]$$where [TeX:] $$a_{i, j}=\left\{a_{i, j}^{1}, a_{i, j}^{2}, \ldots, a_{i, j}^{q}\right\}$$, here [TeX:] $$i, j=1,2, \ldots, l \text { and } i \neq j$$.

The rough boundary interval of [TeX:] $$a_{i, j}^{k} \in a_{i, j}(k=1,2, \ldots, q)$$ is obtained as follows:

where [TeX:] $$a_{i, j}^{k,-}$$ is the rough lower limit of [TeX:] $$a_{i, j}^{k}$$ in set [TeX:] $$a_{i, j}^{k,+}$$ is the rough upper limit of [TeX:] $$a_{i, j}^{k}$$ in set [TeX:] $$a_{i, j}$$.

Therefore, the rough boundary interval of [TeX:] $$a_{i, j}$$ can be represented as follows:

##### (9)

[TeX:] $$R N\left(a_{i, j}\right)=\left\{\left[a_{i, j}^{1,-}, a_{i, j}^{1,+}\right],\left[a_{i, j}^{2,-}, a_{i, j}^{2,+}\right], \cdots,\left[a_{i, j}^{q,-}, a_{i, j}^{q,+}\right]\right\}$$Based on the operational rule of rough boundary interval, the average form of [TeX:] $$R N\left(a_{i, j}\right)$$ is obtained as follows:

##### (10)

[TeX:] $$\operatorname{Arg}_{-} R N\left(a_{i, j}\right)=\left[a_{i, j}^{-}, a_{i, j}^{+}\right]=\left[\frac{\sum_{k=1}^{q} a_{i, j}^{k,-}}{q}, \frac{\sum_{k=1}^{q} a_{i, j}^{k+}}{q}\right]$$where [TeX:] $$a_{i, j}^{-}$$ is the rough lower limit of set [TeX:] $$a_{i, j} \text { and } a_{i, j}^{+}$$ is the rough upper limit of set [TeX:] $$a_{i, j}$$.

**Step 4:** The rough judgement matrix is constructed as follows:

##### (11)

[TeX:] $$ E A=\begin{bmatrix} {1}& {A v g_{-} R N\left(a_{1,2}\right)}& {\cdots}& {A v g_{-} R N\left(a_{1, l}\right)}&\\ {A v g_{-} R N\left(a_{2,1}\right)}& {1}& {\cdots}& {A v g_{-} R N\left(a_{2, l}\right)}&\\ {\vdots}& {\vdots}& & {\vdots}&\\ {A v g-R N\left(a_{l, 1}\right)}& {A v g_{-} R N\left(a_{l, 2}\right)}& {\cdots}& {1}& \end{bmatrix}$$ EA is divided into EA^{-} and EA^{+}. Here, EA^{-} is the rough lower limit matrix and EA^{+} is the rough upper limit matrix. EA^{-} and EA^{+} are expressed as follows:

##### (12)

[TeX:] $$E A^{-}=\left[\begin{array}{cccc}{1} & {a_{1,2}^{-}} & {\cdots} & {a_{1, l}^{-}} \\ {a_{2,1}^{-}} & {1} & {\cdots} & {a_{2, l}^{-}} \\ {\vdots} & {\vdots} & {} & {\vdots} \\ {a_{l, 1}^{-}} & {a_{l, 2}^{-}} & {\cdots} & {1}\end{array}\right], E A^{+}=\left[\begin{array}{cccc}{1} & {a_{1,2}^{+}} & {\cdots} & {a_{1, l}^{+}} \\ {a_{2,1}^{+}} & {1} & {\cdots} & {a_{2, l}^{+}} \\ {\vdots} & {\vdots} & {} & {\vdots} \\ {a_{l, 1}^{+}} & {a_{l, 2}^{+}} & {\cdots} & {1}\end{array}\right]$$ The eigenvectors corresponding to the maximum eigenvalues of EA^{-} and EA^{+} are obtained respectively as follows:

##### (13)

[TeX:] $$V A^{-}=\left[v a_{1}^{-}, v a_{2}^{-}, \cdots, v a_{l}^{-}\right]^{\mathrm{T}}, V A_{t}^{+}=\left[v a_{1}^{+}, v a_{2}^{+}, \cdots, v a_{l}^{+}\right]^{\mathrm{T}}$$ where [TeX:] $$v a_{i}^{-}$$ are the value of VA^{-} on the i (i=1,2,...,l) dimension and [TeX:] $$v a_{i}^{+}$$ are the value of VA^{+}on the i (i=1,2,...,l) dimension.

Then, we can get that [TeX:] $$g a_{i}=\left(\left|v a_{i}^{-}\right|+\left|v a_{i}^{+}\right|\right) / 2$$, and a set [TeX:] $$G A=\left\{g a_{1}, g a_{2}, \ldots, g a_{l}\right\}$$ is obtained.

**Step 5:** We repeat steps 3 and 4, so [TeX:] $$G B_{t}=\left\{g b_{1}, g b_{2}, \ldots, g b_{l}\right\}, G C=\left\{g c_{1}, g c_{2}, \ldots, g c_{l}\right\} \text { and } G D=\left\{g d_{1}, g d_{2}, \ldots, g d_{l}\right\}$$ can be obtained. Then the adaptive weight of evaluation indexes [TeX:] $$C_{11}, C_{12}, \dots, C_{1 l}$$ with the trapezoidal fuzzy number form are [TeX:] $$z_{1}=\left(g a_{1}, g b_{1}, g c_{1}, g d_{1}\right), z_{2}=\left(g a_{2}, g b_{2}, g c_{2}, g d_{2}\right), \ldots, z_{l}=\left(g a_{l}, g b_{l}, g c_{l}, g d_{l}\right)$$. Here we use gravity model appoach to convert [TeX:] $$z_{i}=\left(g a_{i}, g b_{i}, g c_{i}, g d_{i}\right)(i=1,2, \ldots, l)$$ into real number ri as follows:

##### (14)

[TeX:] $$r_{i}=\frac{\left[\left(g d_{i}\right)^{2}+g d_{i} \cdot g c_{i}+\left(g c_{i}\right)^{2}\right]-\left[\left(g a_{i}\right)^{2}+g a_{i} \cdot \lg b_{i}+\left(g b_{i}\right)^{2}\right]}{3\left(g d_{i}+g c_{i}-g a_{i}-g b_{i}\right)}$$We normalize [TeX:] $$r_{1}, r_{2}, \ldots, r_{l}$$ and can obtain the adaptive weight of evaluation indexes [TeX:] $$C_{1 i}$$ as follows:

**Step 6:** For indexes [TeX:] $$C_{1}, C_{2}, C_{3 \mathrm{and}} \mathrm{C}_{4}$$, we repeat steps 1-5 and obtain the adaptive weights of them as [TeX:] $$\omega\left(C_{1}\right), \omega\left(C_{2}\right), \omega\left(C_{3}\right), \omega\left(C_{4}\right)$$.

##### 3.3 D-S Theory Decision Regulations

By D-S theory, we can deal with the multi-criteria decision problems with uncertainty and incompleteness [24,25]. In the existing researches, it has been certified that a content result can be obtained and the uncertainty of decision can be decreased based on D-S theory [26,29]. According to D-S theory, we define the suppliers to be evaluated [TeX:] $$x_{1}, x_{2}, \dots, x_{i}, \dots, x_{N}$$ as the D-S identification framework [TeX:] $$\Theta=\left\{x_{1}, x_{2}, \ldots, x_{i}, \ldots, x_{N}\right\}$$. All possible subsets of can be expressed by power set 2^{}. When all elements in are incompatible and independent with each other, the number of elements in 2^{} is 2^{N}. Then, a set function [TeX:] $$m : 2^{\Theta} \rightarrow[0,1]$$, which satisfies [TeX:] $$m(\phi)=0 \text { and } \sum_{A \subset \Theta} m(A)=1$$ , is defined. Here, m is known as the basic probability allocation (BPA) function on and A is a supplier to be evaluated. m(A), which is the BPA value of A, represents the trust degree in A. Any supplier to be evaluated satisfying the condition m(A)>0 is called a focal element.

For [TeX:] $$A \subseteq \Theta$$, the fusion rule of finite BPA functions on is as follows:

##### (16)

[TeX:] $$\left(m_{1} \oplus m_{2} \oplus \ldots \oplus m_{n}\right)(A)=\frac{1}{K} \sum_{A_{1} \cap A_{2} \cap \cdots A_{n}=A}\ m_{1}\left(A_{1}\right) \cdot m_{2}\left(A_{2}\right) \cdot \ldots \cdot m_{n}\left(A_{n}\right)$$K is the normalization constant and is expressed as follows:

##### (17)

[TeX:] $$K=\sum_{A_{1} \cap A_{2} \cap \ldots \cap A_{n} \neq \phi}\ m_{1}\left(A_{1}\right) \cdot m_{2}\left(A_{2}\right) \cdot \ldots \cdot m_{n}\left(A_{n}\right)=\ =1-\sum_{A_{1} \cap A_{2} \cap \ldots \cap A_{n}=\phi}\ m_{1}\left(A_{1}\right) \cdot m_{2}\left(A_{2}\right) \cdot \ldots \cdot m_{n}\left(A_{n}\right)$$The overall trust degree of A on can be represented as a belief function [TeX:] $$\operatorname{Bel}(A)=\sum_{B \subseteq A} m(B)$$ where [TeX:] $$B \subset \Theta$$, and the uncertainty degree of A on can be represented as a plausible function [TeX:] $$P l(A)=\sum_{B \cap A \neq \phi} m(B) \text { where } B \subset \Theta$$.

For a supplier A on , Bel(A) shows the sum of the possibility estimate of all its subsets, and Pl(A) shows the sum of the uncertainty estimate of all its subsets. For A, the degree of confirmation can be expressed by the trust interval [Bel(A), Pl(A)].

According to the above analysis, the sum of credibility which the evidences support A is shown by Bel(A) and the sum of credibility which the evidences does not negative A is shown by Pl(A). Thus, the trust interval is formed as [Bel(A), Pl(A)]. The support degree to a supplier of belief function and plausible function can be reflected by [Bel(A), Pl(A)] comprehensively.

According to references [30,31], to evaluate the suppliers by trust interval approach is more reasonable than max-belief-function decision-making approach or max-plausible-function decision-making approach. The D-S theory decision regulations based on trust interval for supplier evaluation in GSC are as follows.

(i) It is assumed that supplier A_{i} is better than supplier A_{j} with a degree of [TeX:] $$P\left(A_{i}>A_{j}\right)$$. The trust interval of A_{i} is [Bel(A_{i}), Pl(A_{i})], and the trust interval of A_{j} is [Bel(A_{j}), Pl(A_{j})]. [TeX:] $$P\left(A_{i}>A_{j}\right)$$ is obtained as follows:

##### (18)

[TeX:] $$P\left(A_{i}>A_{j}\right)=\frac{\max \left[0, P l\left(A_{i}\right)-\operatorname{Bel}\left(A_{j}\right)\right]-\max \left[0, \operatorname{Bel}\left(A_{i}\right)-P l\left(A_{j}\right)\right]}{\left[P l\left(A_{i}\right)-\operatorname{Bel}\left(A_{i}\right)\right]+\left[P l\left(A_{j}\right)-\operatorname{Bel}\left(A_{j}\right)\right]}$$where [TeX:] $$P\left(A_{i}>A_{j}\right) \in[0,1]$$.

(ii) The partial order relationship: (a) When [TeX:] $$P\left(A_{i}>A_{j}\right)>0.5$$, A_{i} is better than A_{j}, which is expressed as A_{i} A_{j} ; (b) When [TeX:] $$P\left(A_{i}>A_{j}\right)>0.5 \text { and } P\left(A_{j}>A_{k}\right)>0.5, A_{i}$$ is better than A_{k}, which is expressed as A_{i} A_{j} A_{k}.

##### 3.4 Supplier Evaluation Based on D-S Theory

The weighted BPA value of focal element [TeX:] $$A_{i}\left(i<2^{N}\right)$$ under index [TeX:] $$t(t \in I F)$$, which is [TeX:] $$\tilde{m}_{t}\left(A_{i}\right)$$, is introduced into the D-S theory model as evidence input. The calculating and processing approaches for weighted BPA value of each focal element are as follows.

Based on investigating the actual status of each supplier, the expert gives the initial value of indexes which belongs to quantitative type or direct qualitative type. Here, the indexes which belong to definite quantitative type or direct qualitative type are assigned exact values, the indexes which are relatively fuzzy quantitative type are assigned value intervals, and the indexes which are completely unknown are assigned null value. By membership approach, we can calculate the tendency degree of the initial index value.

To an index, five levels of expert’s remark are given as: {G_{1},G_{2},G_{3},G_{4},G_{5}}={very bad, bad, middle, good,very good}. Here, G_{1} is the remark level corresponding to the minimum initial index value D_{1}, and G_{5} is the remark level corresponding to the maximal initial index value G_{5}. However, to cost-based index C_{11}, G_{1} is the remark level corresponding to the maximal initial index value D_{1}, and G_{5} is the remark level corresponding to the minimum initial index value D_{5}.

We assume that the corresponding exact numbers of the five levels of expert’s remark are: [TeX:] $$E\left(G_{1}\right)=0,E\left(G_{2}\right)=0.25, E\left(G_{3}\right)=0.5, E\left(G_{4}\right)=0.75, \text { and } E\left(G_{5}\right)=1$$. The membership degree of the initial index value to G_{i} is defined as _{i}. On t, the tendency degree of A_{i} is expressed as [TeX:] $$P_{t}\left(A_{i}\right)$$, and the calculation of [TeX:] $$P_{t}\left(A_{i}\right)$$ is divided into two circumstances as follows:

(1) Index t belongs to quantitative type.

In this circumstance, the initial index value of A_{i} on t is a point-value a or an value-interval [a,b].

If [TeX:] $$D_{i} \leq a \leq D_{i+1} \text { or } D_{i} \leq a \leq b \leq D_{i+1}, P_{t}\left(A_{i}\right)=\beta_{i} E\left(G_{i}\right)+\beta_{i+1} E\left(G_{i+1}\right)$$.

If [TeX:] $$D_{i} \leq a \leq D_{i+1} \text { and } D_{i+1} \leq b \leq D_{i+2}, P_{t}\left(A_{i}\right)=\beta_{i} E\left(G_{i}\right)+\beta_{i+1} E\left(G_{i+1}\right)+\beta_{i+2} E\left(G_{i+2}\right)$$.

If [TeX:] $$D_{i} \leq a \leq D_{i+1} \text { and } D_{j} \leq b \leq D_{j+1}, P_{t}\left(A_{i}\right)=\beta_{i} E\left(G_{i}\right)+\beta_{i+1} E\left(G_{i+1}\right)+\ldots+\beta_{j} E\left(G_{j}\right)+\beta_{j+1} E\left(G_{j+1}\right)$$.

(2) Index t belongs to direct qualitative type.

In this circumstance, the tendency degree of A_{i} on t is equal to the number corresponding to the remark level.

By the above approach, the tendency degree of each focal element except under any index can be solved. Here, the expert’s uncertainty is indicated by . Without the consideration of the influence of , the supplier evaluation problem is a simple probability allocation problem. However, the advantages of D-S theory in solving multiple indexes decision problem are not reflected. Simultaneously, the trust degree of expert on any index is different and the uncertainty of an index is expressed by the probability allocation of

Thus, the probability allocation value of on different indexes should also be considered differently. For example, in the supplier evaluation problem, the weight of evaluation index is obviously variable in different requirements. If cost reduction is needed, C_{11} will be more important and its trust degree should be larger. The BPA value of on C_{11} should be smaller. Accordingly, we introduce the adaptive weight (determined in Section 3.2) to regulate the preference of each index and solve the probability allocation problem of on all indexes, then the weighted BPA value of every focal element on any index is calculated as [TeX:] $$\tilde{m}_{t}\left(A_{i}\right)$$.

We assume that the adaptive weight of t is [TeX:] $$\omega_{t}\left(\omega_{t} \in(0,1)\right)$$. The bigger w_{t} is, the higher the trust degree of expert to t, the lower the uncertainty of t is, and vice versa. Therefore, a weighted normalization processing of the BPA values of all focal elements is taken as follows:

##### (19)

[TeX:] $$\left\{\begin{array}{cl}{\tilde{m}_{t}\left(A_{i}\right)=\frac{\omega_{t} P_{t}\left(A_{i}\right)}{\sum_{i=1}^{l-1} P_{t}\left(A_{i}\right)}} & {A_{i} \neq \Theta} \\ {\tilde{m}_{t}\left(A_{i}\right)=1-\omega_{t}} & {A_{i}=\Theta}\end{array}\right.$$ According to Fig. 1, the evidences of C_{11},C_{12},C_{13} and C_{14} of C_{1} are fused and processed, and then the weighted BPA value of C_{1} is calculated as [TeX:] $$\tilde{m}_{1}\left(A_{i}\right)$$. After that, we execute a secondary fusion which includes the weighted BPA value of C_{1},C_{2},C_{3} and C_{4}, and the evaluation result of suppliers can be obtained.

## 4. Case Study

As an important part of modern mechanical equipment, the main function of bearing is to sustain the mechanical revolving body, depress the friction in movement and ensure the rotary precision. A bearing manufacturing enterprise has three candidate bearing-cage suppliers. To select the optimal bearing-cage supplier, supplier evaluation should be executed.

Firstly, the adaptive weight of evaluation index is determined by our designed fuzzy-rough-sets-AHP method. Four experts (expert 1, expert 2, expert 3, and expert 4) participate in the judgment on C_{11},C_{12},C_{13} and C_{14}. Using the proportional scale method of trapezoidal fuzzy number [21], the trapezoidalfuzzy- number reciprocal judgment matrices E_{1}, E_{2}, E_{3}, and E_{4} are shown as follows.

Taking E^{1} for example, it can be converted to the following form:

After consistency check, E^{1}, E^{2}, E^{3} and E^{4} are all qualified. Then they are split, and a^{1} is as follows:

Based on a^{1}, a^{2}, a^{3} and a^{4}, the rough group-decision matrix is obtained as follows:

In element [TeX:] $$a_{1,4}=\{3 / 2,1,1,7 / 3\}$$, the upper approximation set of partition '3/2' is {3/2,7/3} and the lower approximation set of partition '3/2' is {3/2,1,1}, so [TeX:] $$\underline{L} \quad\left(3 / 2^{\prime}\right)=(3 / 2+1+1) / 3=1.17$$, [TeX:] $$\overline{L}\left(3 / 2^{\prime}\right)=(3 / 2+7 / 3) / 2=1.92 \text { and } R N\left(3 / 2^{\prime}\right)=[1.17,1.92]$$. Similarly, RN('1')=[1,1.46], RN('7/3')=[1.46,2.33] and [TeX:] $$R N\left(a_{1,4}\right)=\{[1.17,1.92],[1,1.46],[1,1.46],[1.46,2.33]\}$$.

Thus, [TeX:] $$A v g_{-} R N\left(a_{1,4}\right)=[1.16,1.79]$$. The rough boundary intervals in average form of other elements of a can be also calculated. The rough judgment matrix is constructed as follows:

Then EA is split into EA^{-} and EA^{+}. The eigenvector corresponding to the maximum eigen-value of EA^{-} is [TeX:] $$V A^{-}=[0.71,0.44,0.45,0.30]^{\mathrm{T}}$$ and the eigenvector corresponding to the maximum eigen-value of EA^{+} is [TeX:] $$ V A^{+}=[0.65,0.49,0.47,0.34]^{\mathrm{T}}$$. So GA={0.68,0.47,0.46,0.32}. Similarly, GB={0.73,0.51,0.66,0.58}, GC={0.82,0.67,0.73,0.69} and GD={0.95,0.77,0.83,0.75}. Then the adaptive weight of indexes C_{11},C_{12},C_{13} and C_{14} with the trapezoidal fuzzy number form are [TeX:] $$z_{1}=(0.68,0.73,0.82,0.95), z_{2}=(0.47,0.51,0.67,0.77), z_{3}=(0.46,0.66,0.73,0.83) \text { and } z_{4}=(0.32,0.58,0.69,0.75)$$. After gravity model approach processing and normalization processing, we obtain the adaptive weight of evaluation indexes C_{11},C_{12},C_{13} and C_{14}: [TeX:] $$\omega\left(C_{11}\right)=0.30, \omega\left(C_{12}\right)=0.23, \omega\left(C_{13}\right)=0.25, \text { and } \omega\left(C_{14}\right)=0.22$$. Similarly, the adaptive weights of criterions C_{1},C_{2},C_{3} and C_{4} are [TeX:] $$\omega\left(C_{1}\right)=0.57, \omega\left(C_{2}\right)=0.18, \omega\left(C_{3}\right)=0.26, \text { and } \omega\left(C_{4}\right)=0.09$$.

Secondly, we use the proposed adaptive weight D-S theory model to deal with the decision of supplier evaluation problem. For the three candidate suppliers, their initial index values are shown in Table 1.

Corresponding to the remark level [TeX:] $$\left\{G_{1}, G_{2}, G_{3}, G_{4}, G_{5}\right\}$$, the reference values of the index belonging to quantitative type are as follows: [TeX:] $$G\left(C_{11}\right)=\left\{10^{5}, 10^{4}, 10^{3}, 10^{2}, 10^{1}\right\}, G\left(C_{12}\right)=\{0.05,0.04,0.03,0.02,0.01\}$$, [TeX:] $$G\left(C_{2}\right)=\{17,13,9,5,1\}, G\left(C_{3}\right)=\{1,3,5,7,9\} \text { and } G\left(C_{4}\right)=\{0,0.25,0.5,0.75,1\}$$.

Then, the membership degree of initial index value to every remark level is obtained. The data in Table 1 is translated into the membership degree form corresponding to remark grade. As shown in Table 2, the tendency degree form of initial index value is obtained.

We define the set of candidate suppliers as the D-S theory identification framework: [TeX:] $$\Theta=\left\{x_{1}, x_{2}, x_{3}\right\}$$, Here, x_{1},x_{2} and x_{3} represent bearing-cage suppliers 1, 2, and 3, respectively.

For four indexes C_{11},C_{12},C_{13} and C_{14} and three criterions C_{2},C_{3}, and C_{4}, the weighted BPA values of all focal elements are obtained according to the tendency degree shown in Table 2 and the weight vectors [TeX:] $$\left(\omega\left(C_{11}\right), \omega\left(C_{12}\right), \omega\left(C_{13}\right), \omega\left(C_{14}\right)\right)=(0.30,0.23,0.25,0.22), \text { and }\left(\omega\left(C_{2}\right), \omega\left(C_{3}\right), \omega\left(C_{4}\right)\right)=(0.18,0.26,09)$$. The calculation result is as follows:

(1) C_{11}: [TeX:] $$\tilde{m}_{11}\left(x_{1}\right)=0.1672, \quad \tilde{m}_{11}\left(x_{2}\right)=0.0934, \quad \tilde{m}_{11}\left(x_{3}\right)=0.0393, \quad \tilde{m}_{11}(\Theta)=0.7000$$

(2) C_{12}: [TeX:] $$\tilde{m}_{12}\left(x_{1}\right)=0.0920, \quad \tilde{m}_{12}\left(x_{2}\right)=0.0920, \quad \tilde{m}_{12}\left(x_{3}\right)=0.0460, \quad \tilde{m}_{12}(\Theta)=0.7700$$

(3) C_{13}: [TeX:] $$\tilde{m}_{13}\left(x_{1}\right)=0.1071, \tilde{m}_{13}\left(x_{2}\right)=0.1429, \quad \tilde{m}_{13}\left(x_{3}\right)=0, \quad \tilde{m}_{13}(\Theta)=0.7500$$

(4) C_{14}: [TeX:] $$\tilde{m}_{14}\left(x_{1}\right)=0, \quad \tilde{m}_{14}\left(x_{2}\right)=0.1100, \tilde{m}_{14}\left(x_{3}\right)=0.1100, \tilde{m}_{14}(\Theta)=0.7800$$

(5) C_{2}: [TeX:] $$\tilde{m}_{2}\left(x_{1}\right)=0.0739, \quad \tilde{m}_{2}\left(x_{2}\right)=0.0744, \quad \tilde{m}_{2}\left(x_{3}\right)=0.0317, \quad \tilde{m}_{2}(\Theta)=0.8200$$

(6) C_{3}: [TeX:] $$\tilde{m}_{3}\left(x_{1}\right)=0.1300, \quad \tilde{m}_{3}\left(x_{2}\right)=0.1300, \quad \tilde{m}_{3}(\Theta)=0.7400$$

(7) C_{4}: [TeX:] $$\tilde{m}_{4}\left(x_{1}\right)=0.0297, \tilde{m}_{4}\left(x_{2}\right)=0.0302, \tilde{m}_{4}\left(x_{3}\right)=0.0302, \tilde{m}_{4}(\Theta)=0.9100$$

After that, we take [TeX:] $$\tilde{m}_{11}\left(x_{i}\right), \tilde{m}_{12}\left(x_{i}\right), \tilde{m}_{13}\left(x_{i}\right), \text { and } \tilde{m}_{14}\left(x_{i}\right)$$ as the evidence input and implement the first evidence fusion. The BPA values of all focal elements are obtained as follows: [TeX:] $$m_{1}\left(x_{1}\right)=0.1001,m_{1}\left(x_{2}\right)=0.7815, m_{1}\left(x_{3}\right)=0.0772, m_{1}\left(x_{1}, x_{2}\right)=0.0102, m_{1}\left(x_{2}, x_{3}\right)=0.0201, m_{1}\left(x_{1}, x_{3}\right)=0.0098, \text { and } m_{1}(\Theta)=0.0011.$$

We normalize BPA values [TeX:] $$m_{1}\left(A_{i}\right)$$ of the suppliers to be evaluated and on index C_{1}. With the consideration of [TeX:] $$\omega\left(C_{1}\right)$$, the weighted BPA values are obtained as follows: [TeX:] $$\tilde{m}_{1}\left(x_{1}\right)=0.0571, \tilde{m}_{1}\left(x_{2}\right)=0.4455, \tilde{m}_{1}\left(x_{3}\right)=0.0440, \quad \tilde{m}_{1}\left(x_{1}, x_{2}\right) 0.0058, \quad \tilde{m}_{1}\left(x_{2}, x_{3}\right)=0.0115, \tilde{m}_{1}\left(x_{1}, x_{3}\right)=0.0056, \text { and } \tilde{m}_{1}(\Theta)=0.0006$$.

Then, we take [TeX:] $$\tilde{m}_{1}\left(A_{i}\right), \tilde{m}_{2}\left(A_{i}\right), \tilde{m}_{3}\left(A_{i}\right) \text { and } \tilde{m}_{4}\left(A_{i}\right)$$ as the evidence input and implement the second evidence fusion. The comprehensive BPA values of all focal elements are obtained as follows: [TeX:] $$m\left(x_{1}\right)=0.1255, m\left(x_{2}\right)=0.7088, m\left(x_{3}\right)=0.0102, m\left(x_{1}, x_{2}\right)=0.0999, m\left(x_{2}, x_{3}\right)=0.0032, m\left(x_{1}, x_{3}\right)=0.0506\ and\ m(\Theta)=0.0018_{\circ}$$

[TeX:] $$\operatorname{Bel}\left(A_{i}\right) \text { and } \operatorname{Pl}\left(A_{i}\right)$$ of all suppliers are calculated. Then the trust intervals of all suppliers are obtained as follows:

(1) [TeX:] $$x_{1} :[0.1255,0.2778]$$

(2) [TeX:] $$x_{2} :[0.7088,0.8137]$$

(3) [TeX:] $$x_{3} :[0.0102,0.0658]$$

On the basis of the D-S theory decision regulations, the result is as follows:

(1) [TeX:] $$P\left(x_{1}>x_{2}\right)=0,$$ so x_{1} x_{2}.

(2) [TeX:] $$P\left(x_{1}>x_{3}\right)=1,$$ so x_{3} x_{1}

Therefore, the evaluation result of three suppliers is x_{3} x_{1} x_{2} and supplier 2 is the optimal bearingcage supplier. Thus, the proposed adaptive weight D-S theory model can solve the supplier evaluation problem in GSC even the initial index value is uncertain and incomplete (See in Table 1, the initial values of x_{2} and x_{3} on index C_{2} are interval values and the initial value of x_{3} on index C_{3} is missing).

To verify the effectiveness of the proposed adaptive weight D-S theory model, we use traditional TOPSIS method [18,21] to make a comparison. Because the traditional TOPSIS method can only solve the evaluation problem with certain and complete index value, we replace the interval with its mid-value and ignore the index with missing index value (The initial values of x_{2} and x_{3} on index C_{2} are 15.5 and 7, respectively. Index C3 is ignored). The tendency degree method is still used to process the initial index value. Then, processing of the adaptive weights is executed on the basis of the hierarchical structure shown in Fig. 1 and the final weight vector of C_{11},C_{12},C_{13},C_{14},C_{2} and C_{4} is [TeX:] $$\omega=(0.15,0.11,0.12,0.09,0.18,0.09 )$$ in which index C_{3} is ignored. In Table 3, the weighted index value matrix is obtained.

From Table 3, the positive and negative ideal points are (0.1275, 0.1100, 0.1200, 0.0675, 0.1586, 0.0900) and (0.0300, 0.0330, 0, 0, 0.0675, 0.0886), respectively. So we can obtain the close degree to positive ideal point of each supplier is as follows:

(1) x_{1}:0.7065.

(2) x_{2}:0.7686.

(3) x_{3}:0.2569.

Therefore, the evaluation result of three candidate suppliers by traditional TOPSIS method is x_{3} x_{1} x_{2} and the bearing manufacturing enterprise should choose supplier 2 as the optimal bearing cage supplier. The evaluation results of the proposed adaptive weight D-S theory model and traditional TOPSIS method are consistent. This shows that the proposed adaptive weight D-S theory model is feasible and effective.

## 5. Conclusion

In this paper, an adaptive weight D-S theory model is proposed for the evaluation problem characterized by uncertainty and incompleteness and variable index weight in GSC. In addition, a fuzzyrough- sets-AHP approach is designed to obtain the adaptive index weight. The index framework is established considering of the main factors affecting the supplier evaluation in GSC, which can improve the scientific nature and rationality. The case study and the comparison with TOPSIS show that the optimal supplier of manufacturing enterprise can be correctly selected by the proposed adaptive weight D-S theory model.

## Acknowledgement

This paper is supported by Key Scientific Research Projects in 2017 at North Minzu University (No. 2017KJ22), the Third Batch of Ningxia Youth Talents Supporting Program (No. TJGC2018048), Natural Science Foundation of Ningxia Province (No. NZ17113), and Ningxia First-class Discipline and Scientific Research Project: Electronic Science and Technology (No. NXYLXK2017A07).

## Biography

##### Lianhui Li

https://orcid.org/0000-0001-8634-8689He received his M.E. degree in Vehicle Engineering from Henan University of Science and Technology, China, in 2010 and his Ph.D. degree in Aeronautics and Astronautics Manufacturing Engineering from Northwestern Polytechnical University, China, in 2016. He is currently a lecturer at North Minzu University, China. His current research interests include CAD/CAM and logistics engineering.

## Biography

##### Guanying Xu

https://orcid.org/0000-0002-2528-3700He received his B.S. degree in Computer Science and Engineering from Anhui University of Technology, China, in 2017. He is currently a master’s degree candidate in Computer Science and Engineering at North Minzu University. His current research interests include uncertainty theory, fuzzy decision making, and data stream classification.

## References

- 1 K. Govindan, S. Rajendran, J. Sarkis, P. Murugesan, "Multi criteria decision making approaches for green supplier evaluation and selection: a literature review,"
*Journal of Cleaner Production*, vol. 98, pp. 66-83, 2015.doi:[[[10.1016/j.jclepro.2013.06.046]]] - 2 J. Sarkis, "A strategic decision framework for green supply chain management,"
*Journal of Cleaner Production*, vol. 11, no. 4, pp. 397-409, 2003.doi:[[[10.1016/s0959-6526(02)00062-8]]] - 3 S. Curkovic, "Environmentally responsible manufacturing: the development and validation of a measurement model,"
*European Journal of Operational Research*, vol. 146, no. 1, pp. 130-155, 2003.doi:[[[10.1016/S0377-2217(02)00182-0]]] - 4 S. Mishra, C. Samantra, S. Datta, S. S. Mahapatra, "Multi-attribute group decision-making (MAGDM) for supplier selection using fuzzy linguistic modelling integrated with VIKOR method,"
*International Journal of Services and Operations Management*, vol. 12, no. 1, pp. 67-89, 2012.doi:[[[10.1504/ijsom.2012.046674]]] - 5 Y. Wang, K. Jiang, "Research on supplier evaluation and selection based on combination of weighting method and grey relational TOPSIS method in green supply chain,"
*Journal of Industrial Technological & Economics*, vol. 2016, no. 12, pp. 84-91, 2016.custom:[[[-]]] - 6 G. Buyukozkan, G. Cifci, "A novel fuzzy multi-criteria decision framework for sustainable supplier selection with incomplete information,"
*Computers in Industry*, vol. 62, no. 2, pp. 164-174, 2011.doi:[[[10.1016/j.compind.2010.10.009]]] - 7 C. Bai, J. Sarkis, "Green supplier development: analytical evaluation using rough set theory,"
*Journal of Cleaner Production*, vol. 18, no. 12, pp. 1200-1210, 2010.doi:[[[10.1016/j.jclepro.2010.01.016]]] - 8 M. L. Tseng, A. S. Chiu, "Evaluating firm's green supply chain management in linguistic preferences,"
*Journal of Cleaner Production*, vol. 40, pp. 22-31, 2013.doi:[[[10.1016/j.jclepro.2010.08.007]]] - 9 D. Kannan, K. Govindan, S. Rajendran, "Fuzzy axiomatic design approach based green supplier selection: a case study from Singapore,"
*Journal of Cleaner Production*, vol. 96, pp. 194-208, 2015.doi:[[[10.1016/j.jclepro.2013.12.076]]] - 10 A. Awasthi, S. S. Chauhan, S. K. Goyal, "A fuzzy multicriteria approach for evaluating environmental performance of suppliers,"
*International Journal of Production Economics*, vol. 126, no. 2, pp. 370-378, 2010.doi:[[[10.1016/j.ijpe.2010.04.029]]] - 11 W. C. Yeh, M. C. Chuang, "Using multi-objective genetic algorithm for partner selection in green supply chain problems,"
*Expert Systems with Applications*, vol. 38, no. 4, pp. 4244-4253, 2011.doi:[[[10.1016/j.eswa.2010.09.091]]] - 12 J. Wu, Q. W. Cao, H. Li, "A method for choosing green supplier based on COWA operator under fuzzy linguistic decision-making,"
*Journal of Industrial Engineering & Engineering Management*, vol. 24, pp. 61-65, 2010.custom:[[[-]]] - 13 X. Li, C. Zhao, "Selection of suppliers of vehicle components based on green supply chain," in
*Proceedings of 2009 16th International Conference on Industrial Engineering and Engineering Management*, Beijing, China, 2009;pp. 1588-1591. custom:[[[-]]] - 14 G. E. Yan, "Research on green suppliers' evaluation based on AHP & genetic algorithm," in
*Proceedings of 2009 International Conference on Signal Processing Systems*, Singapore, 2009;pp. 615-619. custom:[[[-]]] - 15 R. J. Kuo, Y. C. Wang, F. C. Tien, "Integration of artificial neural network and MADA methods for green supplier selection,"
*Journal of Cleaner Production*, vol. 18, no. 12, pp. 1161-1170, 2010.doi:[[[10.1016/j.jclepro.2010.03.020]]] - 16 R. J. Kuo, Y. J. Lin, "Supplier selection using analytic network process and data envelopment analysis,"
*International Journal of Production Research*, vol. 50, no. 11, pp. 2852-2863, 2012.doi:[[[10.1080/00207543.2011.559487]]] - 17 G. Buyukozkan, G. Cifci, "A novel hybrid MCDM approach based on fuzzy DEMATEL, fuzzy ANP and fuzzy TOPSIS to evaluate green suppliers,"
*Expert Systems with Applications*, vol. 39, no. 3, pp. 3000-3011, 2012.doi:[[[10.1016/j.eswa.2011.08.162]]] - 18 X. X. Luo, S. H. Peng, "Research on the vendor evaluation and selection based on AHP and TOPSIS in green supply chain,"
*Soft Science*, vol. 25, no. 2, pp. 53-56, 2011.custom:[[[-]]] - 19 T. L. Saaty,
*Analytic Hierarchy Process*, NY: McGraw-Hill, New York, 1980.custom:[[[-]]] - 20 L. Lidinska, J. Jablonsky, "AHP model for performance evaluation of employees in a Czech management consulting company,"
*Central European Journal of Operations Research*, vol. 26, no. 1, pp. 239-258, 2018.doi:[[[10.1007/s10100-017-0486-7]]] - 21 L. Li, R. Mo, Z. Chang, H. Zhang, "Priority evaluation method for aero-engine assembly task based on balanced weight and improved TOPSIS,"
*Computer Integrated Manufacturing Systems*, vol. 21, no. 5, pp. 1193-1201, 2015.doi:[[[10.13196/j.cims.2015.05.005]]] - 22 V. Sangiorgio, G. Uva, F. Fatiguso, "Optimized AHP to overcome limits in weight calculation: building performance application,"
*Journal of Construction Engineering and Management*, vol. 144, no. 2, 2017.doi:[[[10.1061/(asce)co.1943-7862.0001418]]] - 23 X. T. Wang, W. Xiong, "Rough AHP approach for determining the importance ratings of customer requirements in QFD,"
*Computer Integrated Manufacturing Systems*, vol. 16, no. 4, pp. 763-771, 2010.custom:[[[-]]] - 24 G. Shafer,
*A Mathematical Theory of Evidence*, NJ: Princeton University Press, Princeton, 1976.custom:[[[-]]] - 25 R. R. Yager, "On the Dempster-Shafer framework and new combination rules,"
*Information Sciences*, vol. 41, no. 2, pp. 93-137, 1987.doi:[[[10.1016/0020-0255(87)90007-7]]] - 26 L. Liu, T. Bao, J. Yuan, C. Li, "Risk assessment of information security based on Grey incidence and D-S theory of evidence,"
*Journal of Applied Sciences*, vol. 13, no. 10, pp. 1740-1745, 2013.doi:[[[10.3923/jas.2013.1740.1745]]] - 27 M. S. Khan, I. Koo, "the effect of multiple energy detector on evidence theory based cooperative spectrum sensing scheme for cognitive radio networks,"
*Journal of Information Processing Systems*, vol. 12, no. 2, pp. 295-309, 2016.doi:[[[10.3745/JIPS.03.0040]]] - 28 X. Zhang, S. Mahadevan, X. Deng, "Reliability analysis with linguistic data: an evidential network approach,"
*Reliability Engineering & System Safety*, vol. 162, pp. 111-121, 2017.doi:[[[10.1016/j.ress.2017.01.009]]] - 29 X. Zhang, Y. Deng, F. T. Chan, A. Adamatzky, S. Mahadevan, "Supplier selection based on evidence theory and analytic network process,"
*Proceedings of the Institution of Mechanical EngineersPart B: Journal of Engineering Manufacture*, vol. 230, no. 3, pp. 562-573, 2016.doi:[[[10.1177/0954405414551105]]] - 30 R. Mo, D. Zhang, C. Li, "Selection and evaluation of fitting ring in assembly dimensions chain for aircraft based on D-S evidence theory,"
*Computer Integrated Manufacturing System*, vol. 21, no. 9, pp. 2361-2368, 2015.doi:[[[10.13196/j.cims.2015.09.011]]] - 31 Y. M. Wang, J. B. Yang, D. L. Xu, "A preference aggregation method through the estimation of utility intervals,"
*Computers & Operations Research*, vol. 32, no. 8, pp. 2027-2049, 2005.doi:[[[10.1016/j.cor.2004.01.005]]]