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2-Tuple linguistic hybrid arithmetic aggregation operators group decision making

2-Tuple linguistic hybrid arithmetic aggregation operators and application to multi-attribute group decision making

Shu-Ping Wan ?

College of Information Technology,Jiangxi University of Finance and Economics,Nanchang,Jiangxi 330013,China

Jiangxi Key Laboratory of Data and Knowledge Engineering,Jiangxi University of Finance and Economics,Nanchang,Jiangxi 330013,China

a r t i c l e i n f o Article history:

Received 22April 2012

Received in revised form 28January 2013Accepted 1February 2013

Available online 11February 2013Keywords:

Multi-attribute group decision making Linguistic preference

2-Tuple linguistic information Hybrid aggregation operator Arithmetic average operators Geometric average operators

a b s t r a c t

The focus of this paper is on multi-attribute group decision making (MAGDM)problems in which the attribute values,attribute weights,and expert weights are all in the form of 2-tuple linguistic informa-tion,which are solved by developing a new decision method based on 2-tuple linguistic hybrid arithmetic aggregation operator.First,the operation laws for 2-tuple linguistic information are de?ned and the related properties of the operation laws are studied.Hereby some hybrid arithmetic aggregation opera-tors with 2-tuple linguistic information are developed,involving the 2-tuple hybrid weighted arithmetic average (THWA)operator,the 2-tuple hybrid linguistic weighted arithmetic average (T-HLWA)operator,and the extended 2-tuple hybrid linguistic weighted arithmetic average (ET-HLWA)operator.In the pro-posed decision method,the individual overall preference values of alternatives are derived by using the extended 2-tuple weighted arithmetic average operator (ET-WA).Utilized the ET-HLWA operator,all the individual overall preference values of alternatives are further integrated into the collective ones of alter-natives,which are used to rank the alternatives.A real example of personnel selection is given to illus-trate the developed method and the comparison analyses demonstrate the universality and ?exibility of the method proposed in this paper.

ó2013Elsevier B.V.All rights reserved.

1.Introduction

Multi-attribute group decision making (MAGDM)problems with linguistic information arise from a wide range of real-world situations [1–33].There are several kinds of researches on linguis-tic MAGDM,such as linguistic preference MAGDM [4–7],uncertain linguistic MAGDM [8–10],unbalanced linguistic MAGDM [11–14],and 2-tuple linguistic MAGDM [15–30].

Herrera et al.proposed 2-tuple linguistic representation model,which is composed of a linguistic term and a real number [15,17].The 2-tuple linguistic model has exact characteristic in linguistic information processing.It avoided information distortion and los-ing which occur formerly in the linguistic information processing.In recent years,2-tuple linguistic model has been extensively used in group decision making problems [15–30].These researches can be roughly classi?ed into the following three types.

The ?rst type is on information aggregation operators.Herrera

and Mart?

′nez [17]developed 2-tuple arithmetic averaging (TAA)operator,2-tuple weighted averaging (TWA)operator,2-tuple or-dered weighted averaging (TOWA)operator and extended 2-tuple weighted averaging (ET-WA)operator.Chang and Wen [18]pro-posed a novel technique combining 2-tuple and the ordered weighted averaging (OWA)operator for prioritization of failures in a product design failure mode and effect analysis.Wei [19]developed three new aggregation operators:generalized 2-tuple weighted average (G-2TWA)operator,generalized 2-tuple ordered weighted average (G-2TOWA)operator and induced generalized 2-tuple ordered weighted average (IG-2TOWA)operator.Zhang and Fan [20]proposed the extended 2-tuple ordered weighted averag-ing (ET-OWA)operator.Pei et al.[21]analyzed three kinds of weight information,i.e.,belief degrees of linguistic evaluation val-ues,weights of IAEA experts about indicators and strengths of indi-cators and proposed a weighted linguistic aggregation operator.Wei [22]proposed some new geometric aggregation operators:the extended 2-tuple weighted geometric (ET-WG)operator and the extended 2-tuple ordered weighted geometric (ET-OWG)oper-ator and analyzed the properties of these operators.Then,a MAG-DM method was presented based on the ET-WG and ET-OWG operators.Wei and Zhao [23]developed some dependent aggrega-tion operators with 2-tuple linguistic information and applied to MAGDM.Dong et al.[24]suggested that the virtual linguistic var-iable and the 2-tuple linguistic variable can be mutually retrans-lated and then proposed the OWA-based consensus operator under linguistic representation models.Xu et al.[25]adopted the virtual linguistic label to replace 2-tuple linguistic variable and proposed the linguistic power average operators including LPA,LPWA and LPOWA.They further developed the uncertain linguistic power average operators,such as ULPA,ULPWA and ULPOWA.

0950-7051/$-see front matter ó2013Elsevier B.V.All rights reserved.https://www.doczj.com/doc/d7760242.html,/10.1016/j.knosys.2013.02.002

Tel.:+86138********.

E-mail address:shupingwan@https://www.doczj.com/doc/d7760242.html,

The second type is on multi-granularity linguistic information. Herrera and Mart?′nez[26]proposed another method to solve the group decision making problem with multi-granularity linguistic information.They constructed linguistic hierarchy term sets and generalized transformation functions to unify the multi-granular-ity linguistic information into the linguistic2-tuples.Herrera et al.[27]investigated a fusion method based on the linguistic2-tuple representation model to handle the multi-granularity lin-guistic information.Gramajo and Mart?′nez[28]proposed a linguis-tic decision support model for traf?c prioritization in networking.

The third type is on incomplete weight information.Wei et al.

[29]investigated the MAGDM problems with2-tuple linguistic assessment information,in which the information about attribute weights is incompletely known,and the attribute values take the form of linguistic assessment information.Wei[30]proposed the grey relational analysis method for2-tuple linguistic MAGDM with incomplete weight information.

In most of the proposals for solving MAGDM problems with2-tuple linguistic information found in literature,the importance de-grees of experts(or decision makers)are usually represented by a numerical weighting vector or absolutely unknown(i.e.,do not consider the importance degrees of different experts).In group decision making problems,if the weighting vector is known, weighted aggregating strategy is usually used to associate with the vector;if the weighting vector is absolutely unknown,the OWA strategy is often used.Different experts generally act as dif-ferent roles in the decision making process since the experts have their different cultural,educational backgrounds,experiences and knowledge,and expertise related with the problem domain.In addition,it is more reasonable and natural to use linguistic vari-ables for representing the importance degrees of experts,such as ‘‘very important’’,‘‘important’’.However,most of existing aggrega-tion operators for2-tuples did not consider the weighted vector in the form of linguistic variables or2-tuples.To overcome this draw-back,this paper develops some new hybrid arithmetic aggregation operators for2-tuples and then proposes a new method for MAG-DM problems with2-tuple linguistic assessments.The motivation of this paper is based on the following facts:

(i)The existing aggregation operators with2-tuple linguistic

information are mainly focused on the weighted arithmetic (geometric)average and the ordered weighted arithmetic (geometric)average operators.There was less investigation about the hybrid aggregation operators with2-tuple linguis-tic information.

(ii)The hybrid aggregation operators can re?ect the important degrees of both the given2-tuples and the ordered positions of the2-tuples,and then are more generalized operators.

They are usually used to integrate the individual overall preference values of alternatives into the collective ones of alternatives.To do so,each individual overall preference value should?rst be weighted by using the corresponding expert’s weight,which can suf?ciently re?ect the impor-tance degrees of different experts.

(iii)Wei[22]only considered the weight information of attri-butes in the form of the linguistic variables and didn’t con-sider the weight information of experts.The MAGDM method[22]can not deal with the case that the weight

information of attributes and experts takes the form of the 2-tuples.However,this case may appear in some real-life decision problems(see Section5).These new hybrid arith-metic aggregation operators for2-tuples proposed in this paper can be used to effectively dispose this case.

(iv)The proposed method in this paper is more reasonable and ?exible than the existing ones and can be applicable to real-life decision problems in many areas such as risk invest-ment,performance evaluation of military system,engineer-ing management,and supply chain.

The rest of the paper is arranged as follows.Section2introduces the notions for2-tuple linguistic information,and gives the opera-tion laws and analyzes the properties of the operation laws.Sec-tion3presents the existing arithmetic aggregation operators for 2-tuple linguistic information and further develops some new2-tuple linguistic hybrid arithmetic aggregation operators.Section4 proposes the MAGDM method with2-tuple linguistic assessments.

A real personnel selection example is illustrated in Section5.The comparison analyses with other methods are conducted in Sec-tion6.Concluding remark is made in Section7.

2.2-Tuple linguistic information

2.1.Notions for2-tuple linguistic information

De?nition1([15,17]).Let S={s0,s1,s2,...,s t}be a?nite and totally ordered discrete linguistic term set with odd cardinality, where s i represents a possible value for a linguistic variable. b2[0,t]is a number value representing the aggregation result of linguistic symbolic.Then the function D used to obtain the2-tuple linguistic information equivalent to b is de?ned as:

D:?0;t !S??à0:5;0:5T

b!DebT?es i;aT

e1T

where i=round(b),a=bài,a2[à0.5,0.5),round(á)is the usual round operation.s i has the closest index label to b and a is the value of the symbolic translation.

De?nition2([15,17]).Let S={s0,s1,s2,...,s t}be a linguistic term set and(s i,a)be a linguistic2-tuple.There is always a function Dà1,such that,from a2-tuple it returns its equivalent numerical value b2[0,t]&R,which is

Dà1:S??à0:5;0:5T#?0;t

Dà1es i;aT?ita?b:e2TFrom De?nitions1and2,we can conclude that the conversion of a linguistic term into a linguistic2-tuple consists of adding a value0 as symbolic translation:

Des iT?es i;0T:e3T

De?nition3([15,17]).Let(s k,a k)and(s l,a l)be two2-tuples,they should have the following properties

Table1

The collective overall preference values of alternatives obtained by the methods of[22]and this paper.

Alternatives A1A2A3A4A5Ranking result Wei[22](s4,à0.25)(s3,0.43)(s4,0.15)(s4,0.33)(s4,à0.32)A41A31A11A51A2 This paper(s4,0.1923)(s4,à0.2500)(s5,à0.3269)(s5,à0.4116)(s4,0.1308)A31A41A11A51A2 32S.-P.Wan/Knowledge-Based Systems45(2013)31–40

(1)If k

(s k,a k)<(s l,a l);

(2)If k>l then(s k,a k)is bigger than(s l,a l),denoted by

(s k,a k)>(s l,a l);

(3)If k=l then

(a)If a k=a l,then(s k,a k)and(s l,a l)represent the same infor-

mation,denoted by(s k,a k)=(s l,a l);

(b)If a k

(c)If a k>a l,then(s k,a k)>(s l,a l).

To preserve all the given information,we extend the discrete term set S to a continuous term set S?f s l j s06s l6s q;l2?0;q g, where q P t and q is a suf?ciently large positive integer,whose ele-ments also meet all the characteristics above.If s l2S,then we call s l the original term,otherwise,we call s l the virtual term.In gen-eral,the decision maker uses the original linguistic term to evalu-ate attributes and alternatives,and the virtual linguistic terms can only appear in calculation[4,10].

2.2.Operation laws and properties for2-tuple linguistic information De?nition4.Let(s k,a k)and(s l,a l)be two2-tuples and k P0.Then the operation laws for2-tuples are de?ned as follows:

(1)(s k,a k)è(s l,a l)=D(Dà1(s k,a k)+Dà1(s l,a l));

(2)(s k,a k) (s l,a l)=D(Dà1(s k,a k)áDà1(s l,a l));

(3)k(s k,a k)=D(k Dà1(s k,a k));

(4)(s k,a k)k=D((Dà1(s k,a k))k);

(5)es k;a kTes l;a lT?DeeDà1es k;a kTTDà1es l;a lTT.

Remark 1.It should be noted that if the2-tuple linguistic information comes from different linguistic term sets(i.e.multi-granularity linguistic information),they have to be converted into the fuzzy sets de?ned in the basic linguistic term set by means of a transformation function[27],then they can be operated using the above operation laws.To avoid the operation results of De?nition4 being out of the scope[s0,s q],we can make the cardinality q+1of the extended continuous term set S large enough.

If all2-tuples(s k,a k)and(s l,a l)in De?nition4are reduced to linguistic labels s k and s l,i.e.,a k=0and a l=0,then the operation laws in De?nition4are reduced to the following operation laws:

(1)s kès l=s k+l;

(2)s k s l?s k

l

;

(3)k s k=s k k;

(4)es kTk?s

k k ;

(5)es kTs l?s

k l

.

The above are just the operation laws for linguistic labels de?ned in[4–6,32],which shows the justi?cation of De?nition4to some degree.As far as we know,however,there is less investigation on the operation laws of2-tuples.De?nition4gives the operation laws of2-tuples,which can be used for direct calculation of2-tuple linguistic information.We insist that this is an interesting and valuable work for2-tuples though it is a generalization of the operation algorithms in[4–6,32],even if it is a formal transformation.

In the following,suppose that a given linguistic term set is S={s0,s1,s2,...,s8},we give some examples to illustrate the above De?nition4.

Example 1.(s1,0.1)è(s3,0.2)=D(Dà1(s1,0.1)+Dà1(s3,0.2))= D(4.3)=(s4,0.3).Example3.2(s2,0.3)=D(2Dà1(s2,0.3))=D(2?2.3)=D(4.6)= (s5,à0.4).

Example 4.(s2,0.3)2=D((Dà1(s2,0.3))2)=D(2.32)=D(5.29)= (s5,0.29).

Example 5.es1;0:1Tes3;0:2T?DeeDà1es1;0:1TTDà1es3;0:2TT?De1:13:2T?De1:3566T?es1;0:3566T:

From De?nition4,the following Theorem1can be easily proven:

Theorem1.Let(s k,a k),(s l,a l)and(s i,a i)be three2-tuples and k, k P0.The following equalities hold:

(1)(s k,a k)è(s l,a l)=(s l,a l)è(s k,a k);

(2)(s k,a k) (s l,a l)=(s l,a l) (s k,a k);

(3)k((s k,a k)è(s l,a l))=k(s k,a k)èk(s l,a l);

(4)((s k,a k)k)k=(s k,a k)k k,(s k,a k)k (s k,a k)k=(s k,a k)k+k;

(5)[(s k,a k)è(s l,a l)] (s i,a i)=[(s k,a k) (s i,a i)]è[(s l,a l) (s i,a i)];

(6)[(s k,a k) (s l,a l)] (s i,a i)=(s k,a k) [(s l,a l) (s i,a i)].

3.Some arithmetic aggregation operators with2-tuple linguistic information

3.1.The existing2-tuple linguistic arithmetic aggregation operators

Based on De?nitions2and3,the existing arithmetic aggrega-tion operators with2-tuple linguistic information are presented in this subsection.For convenience,let T be the set of all2-tuples. De?nition5[17].Let x={(r1,a1),(r2,a2),...,(r n,a n)}be a set of2-tuples,the2-tuple arithmetic averaging TAA is de?ned as

TAAeer1;a1T;er2;a2T;...;er n;a nTT?D

1

n

X n

j?1

Dà1er j;a jT

!

:e4T

De?nition6[17].Let x={(r1,a1),(r2,a2),...,(r n,a n)}be a set of2-tuples,and w=(w1,w2,...,w n)T be the weight vector of2-tuples

(r j,a j)(j=1,2,...,n),satisfying that06w j61(j=1,2,...,n)and P n

j?1

w j?1.The2-tuple weighted average TWA is de?ned as follows:

TWA weer1;a1T;er2;a2T;...;er n;a nTT?D

X n

j?1

w j Dà1er j;a jT

!

:e5T

Especially,if w j=1/n(j=1,2,...,n),then the TWA operator is re-duced to the TAA operator.

De?nition7[17].Let x={(r1,a1),(r2,a2),...,(r n,a n)}be a set of2-tuples.The2-tuple ordered weighted average(TOWA)operator of dimension n is a mapping TOWA:T n?T so that

TOWA weer1;a1T;er2;a2T;...;er n;a nTT

?D

X n

j?1

w j Dà1er rejT;a rejTT

!

;e6T

where w=(w1,w2,...,w n)T is the weighted vector correlating with TOWA,satisfying that06w j61(j=1,2,...,n)and

P n

j?1

w j?1. (r(1),r(2),...,r(n))is a permutation of(1,2,...,n)such that(r r(jà1), a r(jà1))P(r r(j),a r(j))for any j.

S.-P.Wan/Knowledge-Based Systems45(2013)31–4033

De?nition 8[17].Let x ={(r 1,a 1),(r 2,a 2),...,(r n ,a n )}be a set of 2-tuples,and C =((c 1,b 1),(c 2,b 2),...,(c n ,b n ))T be the linguistic weighting vector of 2-tuples (r j ,a j )(j =1,2,...,n ).The extended 2-tuple weighted average (ET àWA )operator is de?ned as follows:

ET àWA C eer 1;a 1T;er 2;a 2T;...;er n ;a n TT

?D X n j ?1D à1ec j ;b j TD à1er j ;a j T

P j ?1

D ec j ;b j T !:e7T

De?nition 9[20].Let x ={(r 1,a 1),(r 2,a 2),...,(r n ,a n )}be a set of 2-tuples.The extended 2-tuple ordered weighted average (ET àOWA )

operator of dimension n is a mapping ET àOWA :T n ?T so that

ET àOWA L eer 1;a 1T;er 2;a 2T;...;er n ;a n TT

?D X n j ?1D à1el j ;g j TD à1er r ej T;a r ej TT

P j ?1

D el j ;g j T !:e8T

where L =((l 1,g 1),(l 2,g 2),...,(l n ,g n ))T is the linguistic weighted

vector correlating with ET àOWA ,(r (1),r (2),...,r (n ))is a permuta-tion of (1,2,...,n )such that (r r (j à1),a r (j à1))P (r r (j ),a r (j ))for any j .3.2.The proposed hybrid arithmetic aggregation operators with 2-tuple linguistic information

It can be seen from De?nitions 8and 9that the ET àWA oper-ator weights the 2-tuple linguistic arguments while the ET àOWA operator weights the ordered positions of the 2-tuple linguistic arguments instead of weighting the arguments themselves.There-fore,weights represent different aspects in both the ET àWA and ET àOWA operators.However,the two operators consider only one of them.To solve this drawback,based on De?nitions 2–4,some hybrid arithmetic aggregation operators with 2-tuple lin-guistic information are developed in the following.

De?nition 10.Let x ={(r 1,a 1),(r 2,a 2),...,(r n ,a n )}be a set of 2-tuples.If THWA :T n ?T so that

THWA w ;x eer 1;a 1T;er 2;a 2T;...;er n ;a n TT

?D X

n j ?1

ew j D à1er 0r ej T;a 0r ej TTT !;

e9T

where w =(w 1,w 2,...,w n )T is the weighted vector correlating with

THWA ,satisfying that 06w j 61(j =1,2,...,n )and P n

j ?1w j ?1.er 0r ej T;a 0r ej TTis the j th largest 2-tuple of 2-tuples r 0i ;a 0

i àáe1;2;...;n T

with r 0i ;a 0i àá

?n x i er i ;a i T.x =(x 1,x 2,...,x n )T is the weighting vec-tor of 2-tuples (r j ,a j )(j =1,2,...,n ),satisfying that 06x j -61(j =1,2,...,n )and P n

j ?1x j ?1.n is the balancing coef?cient (in this case,if x =(x 1,x 2,...,x n )T becomes ((1/n ,1/n ,...,1/n )),

then r 0i ;a 0i àá

becomes (r i ,a i )(1,2,...,n ).Then the function THWA is called the 2-tuple hybrid weighted arithmetic average operator of dimension n .

Example 6.Assume

that,(r 1,a 1)=(s 1,0.1),(r 2,a 2)=(s 3,0.3),

(r 3,a 3)=(s 2,0.2),(r 4,a 4)=(s 4,0.3),w =(0.2,0.3,0.3,0.2)T

and x =(0.1,0.4,

0.3,0.2)T ,then,r 01;a 01àá?4?0:1es 1;0:1T?es 0;0:44T;r 02;a 02àá

?1:6es 3;0:3T

?es 5;0:28T;r 03;a 03àá?1:2es 2;0:2T?es 3;à0:36T;r 04;a 04àá

?0:8es 4;0:3T?

es 3;0:44T,therefore,r 0r e1T;a 0r e1T ?es 5;0:28T;r 0r e2T;a 0

r e2T ?es 3;0:44T;r 0r e3T;a 0r e3T ?es 3;à0:36Tand r 0r e4T;a 0

r e4T ?es 0;0:44T.Thus,

THWA w ;x eer 1;a 1T;er 2;a 2T;er 3;a 3T;er 4;a 4TT

?D X

4j ?1

w j D à1r 0r ej T;a 0r ej T

!?D e2:968T?es 3;à0:032T:Theorem 2.The TOWA operator is a special case of the THWA operator.

Proof.Let x j =1/n (j =1,2,...,n ),then r 0i ;a 0i àá

?n x i er i ;a i T?er i ;a i Te1;2;...;n T.This completes the proof of Theorem 2.h

Theorem 3.The TWA operator is a special case of the THWA operator.Proof.Let w j =1/n (j =1,2,...,n ),then

THWA w ;x eer 1;a 1T;er 2;a 2T;...;er n ;a n TT?D X n j ?1

1n D à1er 0

r ej T;a 0r ej TT

!?D X n j ?11D à1en x j er j ;a j TT !?D

X n j ?1

1

n x j D à1eer j ;a j TT !?D

X

n j ?1

ex j D à1er j ;a j TT !?TWA x eer 1;a 1T;er 2;a 2T;...;er n ;a n TT;which completes the proof of Theorem 3.h

From Theorems 2and 3,we know that,the THWA operator ?rst

weights the given arguments,then reorders the weighted argu-ments in descending order and weights these ordered arguments,and ?nally aggregates all the weighted arguments into a collective one.The THWA operator generalizes both the TWA operator and the TOWA operator.The THWA operator re?ects the important de-grees of both the given 2-tuples and the ordered positions of the 2-tuples.

De?nition 11.Let x ={(r 1,a 1),(r 2,a 2),...,(r n ,a n )}be a set of 2-tuples.If T àHLWA :T n ?T so that

T àHLWA L ;x eer 1;a 1T;er 2;a 2T;...;er n ;a n TT

?D X n j ?1D à1el j ;g j T

P j ?1D el j ;j T

D à1er 0r ej T;a 0r ej TT ! !;e10T

where L =((l 1,g 1),(l 2,g 2),...,(l n ,g n ))T is the 2-tuple linguistic weighted vector correlating with T àHLWA .er 0r ej T;a 0r ej TTis the j th largest 2-tuple of 2-tuples er 0i ;a 0i Tei ?1;2;...;n Twith er 0i ;a 0i T?n x i er i ;a i T;x ?ex 1;x 2;...;x n TT is the weighting vector of 2-tuples (r j ,a j )(j =1,2,...,n ),satisfying that 06x j 61(j =1,2,...,n )and P n

j ?1x j ?1.n is the balancing coef?cient (in this case,if x =(x 1,-x 2,...,x n )T

becomes (1/n ,1/n ,...,1/n )),then r 0i ;a 0i àágoes to (r i ,a i )(-i =1,2,...,n ).Then the function T àHLWA is called the 2-tuple hybrid linguistic weighted arithmetic average operator of dimen-sion n .

Example 7.Assume

that (l 1,g 1)=(s 3,0.4),(l 2,g 2)=(s 2,0.2),

(l 3,g 3)=(s 1,0.1),(l 4,g 4)=(s 5,0.2),(r 1,a 1)=(s 1,0.1),(r 2,a 2)=(s 3,0.3),(r 3,a 3)=(s 2,0.2),(r 4,a 4)=(s 4,0.3)and x =(0.1,0.4,0.3,0.2)T ,then,r 01;a 01àá?4?0:1es 1;0:1T?es 0;0:44T;r 02;a 02àá

?1:6es 3;0:3T?es 5;0:28T;r 03;a 03àá?1:2es 2;0:2T?es 3;à0:36Tand r 04;a 04àá?0:8es 4;0:3T?es 3;0:44T.Therefore,r 0r e1T; a 0r e1TT?es 5;0:28T;r 0r e2T;a 0r e2T ?es 3;0:44T;r 0r e3T;a 0

r e3T

?es 3;à0:36Tand r 0r e4T;a 0r e4T ?es 0;0:44T.Thus,

T àHLWA L ;x eer 1;a 1T;er 2;a 2T;er 3;a 3T;er 4;a 4TT

?D X 4j ?1D à1el j ;g j T

P j ?1

D el j ;j TD à1r 0r ej T;a 0r ej T ! !?D e5:5808T?es 6;à0:4192T:

Theorem 4.The ET àOWA operator is a special case of the T àHLWA

operator.

34S.-P.Wan /Knowledge-Based Systems 45(2013)31–40

Proof.Let x j =1/n (j =1,2,...,n ),then r 0i ;a 0i àá

?n x i er i ;a i T?er i ;a i T;ei ?1;2;...;n T.This completes the proof of Theorem 4.h De?nition 12.Let x ={(r 1,a 1),(r 2,a 2),...,(r n ,a n )}be a set of 2-tuples.If ET àHLWA :T n ?T so that

ET àHLWA L ;C eer 1;a 1T;er 2;a 2T;...;er n ;a n TT

?D X n j ?1D à1el j ;g j TX n j ?1

D à1el j ;g j T

D à1r 0r ej T;a 0r ej T 0B B B B @1C C C C A 0B B B B @1C C C C A

;e11T

where L =((l 1,g 1),(l 2,g 2),...,(l n ,g n ))T is the 2-tuple linguistic

weighted vector correlating with ET àHLWA .r 0r ej T;a 0

r ej T is the j th largest 2-tuple of 2-tuples er 0i ;a 0i Tei ?1;2;...;n Twith er 0i ;a 0i T?n ec i ;b i T er i ;a i T;C ?eec 1;b 1T;ec 2;b 2T;...;ec n ;b n TTT is the 2-tuple lin-guistic weighting vector of 2-tuples (r j ,a j ),n is the balancing coef?-cient.Then the function ET àHLWA is called the extended 2-tuple hybrid linguistic weighted arithmetic average operator of dimen-sion n .

Example 8.Assume that (l 1,g 1)=(s 3,0.4),(l 2,g 2)=(s 2,0.2),(l 3,g 3)=(s 1,0.1),(l 4,g 4)=(s 5,0.2),(r 1,a 1)=(s 3,0.1),(r 2,a 2)=(s 3,0.3),(r 3,a 3)=(s 1,0.2),(r 4,a 4)=(s 2,0.3),(c 1,b 1)=(s 1,à0.4),(c 2,b 2)=(s 0,0.1),(c 3,b 3)=(s 1,0.2)and (c 4,b 4)=(s 1,à0.3),then,er 01;a 01T?4es 1;à0:4T es 3;0:1T?es 3;à0:36T;er 02;a 02T?4es 0;0:1T es 3;0:3T?es 1;0:32T;er 03;a 03T?4es 1;0:2T es 1;0:2T?es 6;à0:24Tand er 04;a 04T?4es 1;à0:3T es 2;0:3T?es 6;0:44T.Therefore,er 0r e1T;a 0r e1TT?es 6;0:44T;er 0r e2T;a 0r e2TT?es 6;à0:24T;er 0r e3T;a 0r e3TT?es 3;à0:36Tand er 0r e4T;a 0r e4TT?es 1;0:32T.Thus,

ET àHLWA L ;C eer 1;a 1T;er 2;a 2T;er 3;a 3T;er 4;a 4TT?D X 4j ?1D à1el j ;g j TP 4j ?1D à1

el j ;g j TD à1er 0r ej T;a 0

r ej TT ! !?D e14:4712T?es 4;à0:2743T:

Remark 2.If the correlated 2-tuple linguistic weighted vector L =((l 1,g 1),(l 2,g 2),...,(l n ,g n ))T in De?nitions 11and 12is reduced to linguistic weighted vector L =(l 1,l 2,...,l n )T ,we can converted L =(l 1,l 2,...,l n )T to 2-tuple linguistic weighted vector L =((l 1,g 1),(l 2,g 2),...,(l n ,g n ))T by using Eq.(3),then De?nitions 11and 12are still validated.

Remark 3.Xu [33]proposed the linguistic hybrid arithmetic aver-aging operator (i.e.,LHAA)for virtual linguistic variables.In the LHAA operator,the weight vector x =(x 1,x 2,...,x n )T of the vir-tual linguistic variables and the associated weight vector w =(w 1,-w 2,...,w n )T are all just in the form of real numbers rather than linguistic variables or 2-tuples.Whereas,for the proposed T-HLWA operator in this paper,the associated weight vector L =((l 1,g 1),(l 2-,g 2),...,(l n ,g n ))T takes the form of 2-tuples;for the proposed ET-HLWA operator in this paper,the associated weight vector L =((l 1,g 1),(l 2,g 2),...,(l n ,g n ))T and the weight vector of 2-tuples C =((c 1,b 1),(c 2,b 2),...,(c n ,b n ))T take the form of 2-tuples.The THWA,T-HLWA and ET-HLWA operators aim at the arguments of 2-tuples while the LHAA operator aims at the arguments of virtual linguistic variables.

If 2-tuple linguistic variable is equivalent to the corresponding virtual linguistic term as stated by Dong et al.[24],then the THWA operator proposed in this paper is equivalent to the LHAA operator,but the LHAA operator can not deal with the weight vectors in the form of linguistic variables or 2-tuples while the T-HLWA and ET-HLWA operators can effectively solve this issue.From this point of view,the T-HLWA and ET-HLWA operators generalization the LHAA operator.

4.MAGDM method with 2-tuple linguistic assessments

4.1.MAGDM problem description using 2-tuple linguistic assessments This section describes the MAGDM problem with 2-tuple lin-guistic assessments.

Let A ={A 1,A 2,...,A m }be a discrete set of m possible alterna-tives and F ={a 1,a 2,...,a n }be a ?nite set of n attributes,where A i denotes the i th alternative and a j denotes the j th attribute.Let D ={D 1,D 2,...,D t }be a ?nite set of t experts,where D k denotes the k th expert.

The expert D k provides his/her assessment information of an

alternative A i on an attribute a j as a 2-tuple r k ij ?s k ij ;a k

ij according

to a prede?ned linguistic term set S ,where s k ij 2S ;a k

ij 2?à0:5;0:5T

ei ?1;2;...;m ;j ?1;2;...;n T.Thus,the experts’assessment infor-mation can be represented by the 2-tuple linguistic decision matri-ces R k

?r k ij

m ?n

ek ?1;2;...;t T.Suppose that both attribute weights and expert weights also can be represented by the 2-tuple linguistic information.Let W =((w 1,h 1),-...,(w n ,h n ))T be the 2-tuple linguistic weight vector of the attributes a j (j =1,2,...,n )and C =((c 1,b 1),(c 2,b 2),...,(c t ,b t ))T be the 2-tuple linguistic weight vector of the experts D k (k =1,2,...,t ),where w j 2S ,c k 2S ,h j 2[à0.5,0.5)and b k 2[à0.5,0.5).

The problem concerned in this paper is how to rank alternatives or select the most desirable alternative(s)among the ?nite set A on the basis of the 2-tuple linguistic decision matrices and the 2-tuple linguistic weight information of attributes and experts.4.2.The decision method with 2-tuple linguistic assessments

In this section,we propose a new method to solve the MAGDM problems with 2-tuple linguistic assessments.An algorithm and process of the MAGDM problems with 2-tuple linguistic assess-ments may be given as follows.

Step 1.Utilized the decision matrix R k and the ET àWA operator,

the individual overall preference value z k i ?s k i ;a k i àá

of the alternative A i is derived as follows:

z k i ?s k i ;a k i àá?ET àWA W s k i 1;a k i 1

àá;...;s k in ;a k in àáàá?D X n j ?1D à1ew j ;h j TP j ?1D ew j ;h j TD à1s k ij ;a k ij !;s k i 2S ;a k

i

2?à0:5;0:5T;

e12T

where W =((w 1,h 1),...,(w n ,h n ))T be the 2-tuple linguistic weight

vector of the attributes a j (j =1,2,...,n ).

Step https://www.doczj.com/doc/d7760242.html,ed the ET àHLWA operator to integrate all the individ-ual overall preference value z k i ?s k i ;a k i àá

ek ?1;2;...;t Tof alternative A i ,the collective overall preference value z i =(s i ,a i )of alternative A i is obtained as follows:

z i ?es i ;a i T?ET àHLWA L ;C s 1i ;a 1

i àá;...;s t i ;a t i

àáàá?D X t j ?1D à1el j ;g j T

P j ?1D el j ;j T

D à1s 0r ej Ti ;a 0r ej Ti !;e13T

where L =((l 1,g 1),(l 2,g 2),...,(l t ,g t ))T is the 2-tuple linguistic

weighted vector correlating with ET àHLWG ;es 0r ej Ti ;a 0r ej T

i Tis the j th largest 2-tuple of 2-tuples s 0k i ;a 0k i àáek ?1;2;...;t Twith s 0k i ;a 0k i àá?t ec k ;b k T s k i ;a k i àáàá

,and C =((c 1,b 1),(c 2,b 2),...,(c t ,b t ))T is the 2-tuple linguistic weight vector of experts D k (k =1,2,...,t ).Step 3.Rank all the alternatives A i (i =1,2,...,m )and select the

best one(s)in accordance with the 2-tuple z i =(s i ,a i )(i =1,2,...,m ).If any alternative has the highest z i value,then,it is the best alternative.

S.-P.Wan /Knowledge-Based Systems 45(2013)31–4035

Remark4.In Step2,we suppose that the weight vector of experts is in the form of2-tuples C=((c1,b1),(c2,b2),...,(c t,b t))T,so the ETàHLWA operator is used to integrate the individual overall pref-erence values of alternative into the collective one.Even if the weight vector of experts is in the form of linguistic labels,the ETàHLWA operator can also be used to obtain the collective one since the linguistic term can be readily transformed into2-tuple by Eq.(3).But if the weight vector of experts is in the form of real numbers,then the TàHLWA operator(i.e.,(10))can be used to obtain the collective one.

Remark 5.Obviously,real number form and2-tuple form are quite different for the weight vector of experts.In order to obtain the collective overall preference values of alternatives,only the ETàHLWA operator can be used for the latter while only the TàHLWA operator for the former.

Remark6.In this paper,we take the weight vector of experts as the2-tuple form.If the2-tuples for the weight vector of experts and for the assessment of attribute values come from different lin-guistic term sets,they should be?rstly converted into the fuzzy sets de?ned in the basic linguistic term set as stated in Remark 1.This solves the normalization problem of the2-tuple weight vec-tor of experts.

5.A real application to a personnel selection problem

In this section,a real personnel selection problem is used to illustrate the proposed method in this paper.

Ahead Software Company Limited was registered in Nanchang, Jiangxi of China.It is a key national project software enterprise and key national high-tech enterprise.Established in1994,it special-izes in research and develop of platform software and trade appli-cation software and selling.The company desires to hire a system analyst from national recruitment.The expert panel consists of two board members D1and D2,Company chairman D3and Company vice chairman D4.Since Company chairman D3has engaged in hu-man resource management for many years and accumulated rich experience,Company chairman D3is named as the group leader which is responsible for the whole recruitment work.

After preliminary screening,?ve candidates(i.e.,alternatives) A i(i=1,2,...,5)remain for further evaluation.Generally,many attributes should be used to evaluate these candidates.To effec-tively and rapidly make decision,three attributes are chosen by the four experts.These attributes are oral communication skills a1,emotional steadiness a2and past experience a3,respectively. Since these attributes are all qualitative attributes,it is reason-able for the experts to use linguistic variables or2-tuples to rep-resent the evaluation information of the candidates with respect to the attributes.Consequently,the?ve candidates are to be evaluated using the2-tuple linguistic information according to the linguistic term set:

S?f s0?extremely poor;s1?very poor;s2?poor;

s3?slightly poor;s4?fairemediumT;

s5?slightly goodeimportantT;s6?goodeimportantT;

s7?very goodeimportantT;s8?extremely goodeimportantTg

by the four experts under these three attributes.The2-tuple lin-guistic decision matrices provided by each expert are respectively as follows:

R1?

es0;0:4Tes3;0:2Tes8;0:1T

es4;0:3Tes1;0:4Tes7;à0:2T

es2;0:2Tes4;0:3Tes6;0:3T

es1;0:3Tes5;à0:4Tes7;0:2T

es7;à0:2Tes8;0:1Tes0;0:1T

B B

B B

B B

B B

@

1

C C

C C

C C

C C

A

;R2?

es2;0:1Tes4;0:2Tes6;0:1T

es5;à0:3Tes3;0:1Tes6;0:2T

es2;0:2Tes7;à0:3Tes6;0:3T

es2;0:3Tes1;0:4Tes7;0:2T

es6;0:2Tes7;à0:1Tes8;0:1T

B B

B B

B B

B B

@

1

C C

C C

C C

C C

A

;

R3?

es4;0:3Tes2;0:4Tes7;0:3T

es3;0:4Tes2;0:1Tes5;à0:2T

es1;0:3Tes4;0:3Tes6;0:3T

es5;0:1Tes8;à0:3Tes7;0:2T

es7;à0:2Tes7;0:4Tes2;0:4T

B B

B B

B B

@

1

C C

C C

C C

A

;R4?

es1;0:3Tes0;0:4Tes7;0:1T

es3;0:3Tes5;0:4Tes8;à0:2T

es1;0:2Tes6;0:2Tes8;0:3T

es1;0:4Tes5;0:3Tes8;à0:2T

es6;0:3Tes3;0:1Tes1;0:3T

B B

B B

B B

@

1

C C

C C

C C

A

:

With ever increasing complexity in real human resource manage-

ment,it is very dif?cult to give precisely the linguistic assessment

information on the expert weights and attribute weights according

to the given linguistic term set in advance.For example,the experts

think that the past experience a3is important and the weight may

be s6but less than s6,thus the weight of attribute a3can be repre-

sented using the linguistic2-tuple(w3,h3)=(s6,à0.2).After the

negotiation and investigation of the experts,they determine the

2-tuple linguistic weight vector W=((w1,h1),(w2,h2),(w3,h3))T of

the attributes,where(w1,h1)=(s8,à0.4),(w2,h2)=(s1,0.3)and

(w3,h3)=(s6,à0.2).

As the stated earlier,Company chairman D3,named as the

group leader,has rich experience,knowledge and speciality in hu-

man resource management.Obviously,his importance degree is

extremely high and may be s8but less than s8,therefore,the

weight of Company chairman D3can be represented using the lin-

guistic2-tuple(c3,b3)=(s8,à0.1).Analogously,the2-tuple linguis-

tic weight vector C=((c1,b1),(c2,b2),(c3,b3),(c4,b4))T of the experts

can be obtained,where(c1,b1)=(s5,0.1),(c2,b2)=(s1,0.2),

(c3,b3)=(s8,à0.1)and(c4,b4)=(s3,0.4).

Next,we adopt the proposed method to solve the above person-

nel selection example.

https://www.doczj.com/doc/d7760242.html,bine the decision matrix R1and the2-tuple linguistic

weight vector of attributes W=((w1,h1),(w2,h2),(w3,h3))T

with the ETàWA operator,the individual overall prefer-

ence value z1

1

?s1

1

;a11

àá

of candidate A1is derived as

follows:

z1

1

?s1

1

;a11

àá

?ETàWA W s1

11

;a111

àá

;s1

12

;a112

àá

;s1

13

;a113

àá

àá

?D

X3

j?1

Dà1ew j;h jT

P3

j?1

Dà1ew j;h jT

Dà1s1

1j

;a11j

!

?es4;à0:3143T:

Likewise,we have

z1

2

?s1

2

;a12

àá

?es5;0:0299T;z1

3

?s1

3

;a13

àá

?es4;0:0034T;z1

4

?s1

4

;a14

àá

?es4;à0:0803T;z1

5

?s1

5

;a15

àá

?es4;0:2714T:

z2

1

?s2

1

;a21

àá

?es4;à0:1361T;z2

2

?s2

2

;a22

àá

?es5;0:1503T;z2

3

?s2

3

;a23

àá

?es4;0:2156T;z2

4

?s2

4

;a24

àá

?es4;0:1537T;z2

5

?s2

5

;a25

àá

?es7;0:0116T:

z3

1

?s3

1

;a31

àá

?es5;0:3156T;z3

2

?s3

2

;a32

àá

?es4;à0:1626T;

z3

3

?s3

3

;a33

àá

?es4;à0:4619T;z3

4

?s3

4

;a34

àá

?es6;0:1585T;

z3

5

?s3

5

;a35

àá

?es5;0:1170T:

z4

1

?s4

1

;a41

àá

?es4;à0:4912T;z4

2

?s4

2

;a42

àá

?es5;0:2612T;

z4

3

?s4

3

;a43

àá

?es4;0:4435T;z4

4

?s4

4

;a44

àá

?es4;0:2701T;

z4

5

?s4

5

;a45

àá

?es4;0:0442T:

Step2.Assume that the correlated2-tuple weighted vector with

ETàHLWA operator is L=((l1,g1),(l2,g2),(l3,g3),(l4,g4))T,

where(l1,g1)=(s2,0.2),(l2,g2)=(s5,0.1),(l3,g3)=(s7,à0.2),

and(l4,g4)=(s6,0.3).Used the2-tuple linguistic weight

vector of experts C=((c1,b1),(c2,b2),(c3,b3),(c4,b4))T and

36S.-P.Wan/Knowledge-Based Systems45(2013)31–40

the ETàHLWA operator to integrate all the individual

overall preference values z k

1?s k

1

;a k1

àá

(k=1,2,3,4)of can-

didate A1,the collective overall preference value of candi-date A1is thus calculated as follows:

z1?ETàHLWA L;C s1

1;a11

àá

;...;s4

1;a41

àáàá

?D

X4

j?1

Dà1el j;g jT

P4

j?1

Dà1el j;g jT

Dà1s0rejT

1

;a0rejT

1

!

?es4;0:2189T:

Similarly,we have

z2?ETàHLWA L;C s1

2;a12

àá

;...;s4

2;a42

àáàá

?D

X4

j?1

Dà1el j;g jT

P

j?1

Del j;

j

T

Dà1es0rejT

2

;a0rejT

2

T

!

?es5;à0:2661T;

z3?ETàHLWA L;C s1

3;a13

àá

;...;s4

3;a43

àáàá

?D

X4

j?1

Dà1el j;g jT

P4

j?1

Dà1el j;g jT

Dà1s0rejT

3

;a0rejT

3

!

?es4;0:0373T;

z4?ETàHLWA L;C s1

4;a14

àá

;...;s4

4;a44

àáàá

?D

X4

j?1

Dà1el j;g jT

P4

j?1

Dà1el j;g jT

Dà1es0rejT

4

;a0rejT

4

T

!

?es5;à0:1673T;

and

z5?ETàHLWA L;C s1

5;a15

àá

;...;s4

5;a45

àáàá

?D

X4

j?1

Dà1el j;g jT

P

j?1

Del j;

j

T

Dà1s0rejT

5

;a0rejT

5

!

?es5;0:1682T:

Step3.Since z5>z4>z3>z1>z2,the ranking result of the candi-dates is A51A41A31A11A2and therefore the best can-

didate is A5,which will be recommended to Ahead

Software Company Limited.

https://www.doczj.com/doc/d7760242.html,parison analyses of the results obtained

https://www.doczj.com/doc/d7760242.html,parison with the approach to MAGDM with linguistic power average operators

Xu et al.[25]proposed four approaches to MAGDM with lin-guistic power average operators.To illustrate the superiorities of the proposed method,we use Approach I of[25]to solve the above personnel selection problem,and then conduct a comparison anal-ysis.The following symbols Sup kh,T k and V k see[25]in detail. Step1:Calculate the matrices Sup kh(k,h=1,2,3,4,k–h)as follows:

Sup12?Sup21?

0:78750:87500:7500 0:95000:78750:9250 1:00000:70001:0000 0:87500:60001:0000 0:92500:85000

B B

B B

B B

B@

1

C C

C C

C C

C A

;

Sup13?Sup31?

0:51250:90000:9000

0:88750:91250:7500

0:88751:00001:0000

0:52500:61251:0000

1:00000:91250:7125

B B

B B

B B

B@

1

C C

C C

C C

C A

;

Sup14?Sup41?

0:88750:65000:8750

0:87500:50000:8750

0:87500:76250:7500

0:98750:91250:9250

0:93750:37500:8500

B B

B B

B@

1

C C

C C

C A;

Sup23?Sup32?

0:72500:77500:8500

0:83750:87500:8250

0:88750:70001:0000

0:65000:21251:0000

0:92500:93750:2875

B B

B B

B@

1

C C

C C

C A;

Sup24?Sup42?

0:90000:52500:8750

0:82500:71250:8000

0:87500:93750:7500

0:88750:51250:9250

0:98750:52500:1500

B B

B B

B B

@

1

C C

C C

C C

A

;

Sup34?Sup43?

0:62500:75000:9750

0:98750:58750:6250

0:98750:76250:7500

0:53750:70000:9250

0:93750:46250:8625

B B

B B

B B

@

1

C C

C C

C C

A

:

Step2:Calculate the matrices T k(k=1,2,3,4)as follows:

T1?

2:18752:42502:5250

2:71252:20002:5500

2:76252:46252:7500

2:38752:12502:9250

2:86252:13751:5625

B B

B B

B@

1

C C

C C

C A;

T2?

2:41252:17502:4750

2:61252:37502:5500

2:76252:33752:7500

2:41251:32502:9250

2:83752:31250:4375

B B

B B

B@

1

C C

C C

C A;

T3?

1:86252:42502:7250

2:71252:37502:2000

2:76252:46252:7500

1:71251:52502:9250

2:86252:31251:8625

B B

B B

B B

@

1

C C

C C

C C

A

;

T4?

2:41251:92502:7250

2:68751:80002:3000

2:73752:46252:2500

2:41252:12502:7750

2:86251:36251:8625

B B

B B

B B

@

1

C C

C C

C C

A

:

Suppose that the weight vector of experts is w=(0.2898,0.0682,

0.4489,0.1932)T.Utilize w to calculate the matrices V k(k=1,2,3,4)

as follows:

V1?

0:29790:29970:2798

0:29070:28860:3076

0:29010:29050:2974

0:31760:32330:2919

0:28990:29530:2772

B B

B B

B@

1

C C

C C

C A;

V2?

0:07010:07050:0659

0:06840:06790:0724

0:06830:06840:0700

0:07470:07610:0687

0:06820:06950:0652

B B

B B

B@

1

C C

C C

C A;

S.-P.Wan/Knowledge-Based Systems45(2013)31–4037

V3?

0:46150:46430:4335 0:45030:44700:4764 0:44940:45000:4607 0:49190:50080:4522 0:44910:45750:4294

B B

B B

B B

@

1

C C

C C

C C

A

;

V4?

0:19860:19980:1866 0:19380:19240:2050 0:19340:19370:1983 0:21170:21550:1946 0:19330:19690:1848

B B

B B

B B

@

1

C C

C C

C C

A

:

Step3:Utilize the LPWA operator to aggregate all the individual decision matrixes into the collective decision matrix as

follows:

R?

s2:5089s2:4495s7:1575

s3:7419s2:5921s6:4264

s1:6049s4:8426s6:8631

s3:3898s6:5916s7:3703

s6:6654s6:8677s1:8271

B B

B B

B B

@

1

C C

C C

C C

A

:

Step4:Suppose that the weight vector of attributes is x=(0.5170,0.0884,0.3946)T.Utilize x,R and the LWA

operator to derive the collective overall preference values

z i(i=1,2,3,4,5)of the alternatives as follows:

z1?s4:3380;z2?s4:6995;z3?s3:9660;z4?s5:2436;z5?s4:7741:

Thus,the ranking result obtained by[25]is A41A51A21A11A3, which is remarkably different from that obtained by this paper. The best alternative by the former is A4while that by the latter is A5.The worst alternative by the former is A3while that by the latter is A2.The main reasons and comparison analysis are made as follows:

(A)Xu et al.[25]proposed Approaches I and II to MAGDM based

on the LPWA and LPOWA operators,respectively.However, different experts assess the alternatives according to the same extended continuous linguistic term set in these approaches.In real-life decision problems,different experts may express their opinions from different granularity lin-guistic term sets.These approaches in[25]did not discuss this case while the proposed method in this paper can be used to solve multi-granularity linguistic MAGDM(as stated in Remarks1and6).

(B)The weighted vectors for LPWA and LPOWA operators are

only in the form of real numbers.That is to say,the four approaches to MAGDM with linguistic power average oper-ators proposed in[25]can only deal with the situation where the weight vectors of attributes and experts are all real numbers rather than linguistic variables or2-tuples.

Whereas,the method proposed in this paper can deal with three cases:linguistic variables,2-tuples and numerical val-ues for the weight information of attributes and experts(see Subsection6.2in detail),which are the notable difference between the method[25]and the method in this paper.

(1)If the weight information of experts is given by linguistic

variables,the linguistic variables can be easily trans-

formed into2-tuples by using Eq.(3),then the

ETàHLWA operator can still be used to integrate the

individual overall preference values of alternatives and

to derive the collective ones of alternatives(see the third

line of Table1in Subsection6.2).

(2)If the weight information of experts is given by2-tuples,

the ETàHLWA operator can be directly used to integrate

the individual overall preference values of alternatives

and to derive the collective ones of alternatives(see

the example of Section5).

(3)If the weight information of experts is given by the real

numbers,we can use the TàHLWA operator to replace

the ETàHLWA operator to derive the collective overall

preference values of alternatives.

For example,suppose that the weight vector of experts is w=(0.2898,0.0682,0.4489,0.1932)T,then used the ETàHLWA operator(i.e.,Eq.(10)),the collective overall preference values of alternatives are obtained as follows:

z1?es4;3953T;z2?es5;à0:4525T;z3?es4;à0:1060T;z4?es5;0:0082T;z5?es5;à0:2061T:

Hence,the ranking order of the alternatives is A41A51A21A1-1A3,which is accordance with that obtained by[25].

In sum,the above discussion demonstrates that the proposed method in this paper is of universality and?exibility.

https://www.doczj.com/doc/d7760242.html,parison with the best related2-tuple MAGDM method

Wei[22]proposed a MAGDM method based on the ET-WG and ET-OWG operators with2-tuple linguistic information.In the follow-ing,to further illustrate the superiorities of the proposed method,we use the method proposed in this paper to solve the investment selec-tion problem of[22],and then conduct a comparison analysis.

An investment company wants to invest a sum of money in the best option.There is a panel with?ve possible alternatives to in-vest the money:a car company A1,a food company A2,a computer company A3,an arms company A4and a TV company A5.The investment company must take a decision according to the four attributes:the risk analysis a1,the growth analysis a2,the social-political impact analysis a3and the environmental impact analysis a4.The?ve possible alternatives A i(i=1,2,3,4,5)are to be evalu-ated using the linguistic term set S={s1=extremely poor(EP);s2-=very poor(VP);s3=poor(P);s4=medium(M);s5=good(G); s6=very good(VG);s7=extremely good(EG)}by three experts D k(k=1,2,3)under the above four attributes.They respectively construct the decision matrices R k?~r k

ij

5?4

ek?1;2;3Tas follows: R1?

M G P P

P VP M P

G M G EP

VG P P G

EG EP VP M

B B

B B

B B

B B

@

1

C C

C C

C C

C C

A

;R2?

P M VP VP

VP EP G G

M G P EG

EG VP VP M

P VP M VP

B B

B B

B B

B B

@

1

C C

C C

C C

C C

A

;

R3?

G P VP VG

VP G P G

VG VP G P

G VG EG VP

M VP M G

B B

B B

B B

@

1

C C

C C

C C

A

:

In[22],the linguistic weight vector of the attributes is

H?es0

3

;s0

1

;s0

2

;s0

4

Tusing the linguistic term set S0?f s0

1

?

extremely important;s0

2

?very important;s0

3

?important;s0

4?medium;s0

5

?bad;s0

6

?very bad;s0

7

?extremely bad g.For the ETàOWG operator[22],the correlated linguistic weighted vector

is taken as V?s0

6

;s0

4

;s0

2

àáT

.

We suppose that the weight vector of experts is x?s04;s04;s05

àáT according to the linguistic term set S0.In addition,for the ETàHL-WA operator of this paper,we also take the correlated linguistic

weighted vector as V?s0

6

;s0

4

;s0

2

àáT

.

38S.-P.Wan/Knowledge-Based Systems45(2013)31–40

Applied the proposed method in this paper,the above linguistic decision matrices,the linguistic weight vectors of the attributes and experts,and the correlated linguistic weighted vector should be?rstly transformed into2-tuple linguistic forms by using Eq.

(3).Then,repeating the same steps as in Section5,the collective overall preference values of alternatives can be obtained.Table1 lists the collective overall preference values of alternatives ob-tained by the method[22]and method in this paper.

It is easily seen from Table1that the ranking results obtained by the method[22]and the method proposed in this paper are slightly different.The difference is the ranking order of A4and A3, i.e.,A41A3by the former while A31A4by the latter.The worst alternative is A2by both methods,but the best alternative by the former is A4,while the best alternative by the latter is https://www.doczj.com/doc/d7760242.html,-pared with the former,the main advantages of the latter mainly lie in the following:

(i)The latter suf?ciently considers the importance degrees of

different experts.Before utilizing the ETàHLWA operator, the individual overall preference values of alternatives should be?rst weighted by the expert weights and then the collective ones of alternatives can be obtained.However, the former is based on the ETàWG and ETàOWG operators, which does not consider the importance degrees of different experts at https://www.doczj.com/doc/d7760242.html,ly,the former supposed that the expert weights are absolutely unknown and used the ETàOWG operators to integrate the individual overall preference val-ues of alternatives into the collective ones.

In real-life decision problems,different experts usually act as different roles in the decision process(such as the expert D3in Section5).Some experts may assign unduly high or unduly low uncertain preference values to their preferred or repugnant objects.To relieve the in?uence of these unfair arguments on the decision results and re?ect the importance degrees of all the experts,the latter?rst weights each indi-vidual overall preference value by using the corresponding expert weight,and then utilizes the ETàHLWA operator to aggregate all the individual weighted overall preference val-ues of each alternative into the collective ones of alterna-tives.Therefore,the ETàHLWA or TàHLWA operator can make the decision results more reasonable through assign-ing low weights to those‘‘false’’or‘‘biased’’arguments.

These advantages can not be re?ected in the former.

(ii)The former is only suitable for the case where the weight information of attributes is the form of the linguistic vari-ables,whereas the latter can deal with the three cases:lin-guistic variables,2-tuples and numerical values for the weight information of attributes and experts(see Subsection

6.1in detail),which also shows that the latter is more uni-

versal and?exible than the former.

https://www.doczj.com/doc/d7760242.html,parison with other normal linguistic MAGDM methods

Ma et al.[31]developed a fuzzy multi-criteria group decision-making(MCGDM)support system,which is called a Decider.By means of existing works on linguistic methods,Ma et al.[31]can deal with subjective and objective information at the same time. The Comparison analyses between[31]and this paper are con-ducted from four aspects.

(a)The research focuses of both papers are quite different.The

former constructed a MCGDM model and developed a fuzzy MCGDM support system under multi-level criteria and multi-level evaluators,while the latter focuses on develop-ing some new2-tuple linguistic hybrid arithmetic aggrega-tion operators.

(b)Although the subjective information in the former may be in

the form of linguistic terms,the linguistic assessment infor-mation is all transformed into fuzzy numbers to deal with them.Any transformation process between linguistic terms and fuzzy numbers may easily result in information losses and distortions to some degree.However,the latter utilizes the proposed2-tuple linguistic hybrid arithmetic aggrega-tion operators to integrate the linguistic assessment infor-mation,which needs not such transformation between linguistic terms and fuzzy numbers.

(c)The former selected the existing aggregation operators

rather than developed news aggregation operators to inte-grate in the MCGDM model,whereas the latter developed some new2-tuple linguistic hybrid arithmetic aggregation operators and applied to the MAGDM.

(d)The former constructed the MCGDM model with multi-level

hierarchies of criteria and evaluators,while the MAGDM model in the latter has only one-level hierarchy of attributes.

Though the former can be applied to many decision problems, such as fabric material ranking,strategy evaluation and non-woven product assessment,then the latter also has some prominent advantages as stated in Subsection6.2in detail.

7.Conclusion

This paper de?ned the operation laws for2-tuples and studied the related properties of the operation laws.After reviewing the existing2-tuple linguistic arithmetic aggregation operators,some hybrid arithmetic aggregation operators with2-tuple linguistic information were developed including THWA,TàHLWA,and ETàHLWA operators.The THWA operator generalizes both the TWA and TOWA operators.The ETàOWA operator is a special case of the TàHLWA operator.

A new decision method was proposed to solve the MAGDM problem with2-tuple linguistic information.The method is based on ETàWA and ETàHLWA operators which can suf?ciently con-sider the importance degrees of different experts and thus relieve the in?uence of those unfair arguments on the decision results. The proposed hybrid arithmetic aggregation operators with2-tu-ple linguistic information enlarge the research content on2-tuple linguistic information and enrich the ideas for solving fuzzy MAG-DM problems with linguistic information.Although the developed method was illustrated using a personnel selection problem,it will be expected to be applicable to decision problems in many areas, especially in situations where multiple experts are involved and the weights of attributes and experts are represented by linguistic variables or2-tuples instead of real numbers,such as the enter-prise project selection and water environment assessment,partner choice in supply chain,and so on.Furthermore,the developed method can also deal with the expert weights in the form of real numbers only if we use the TàHLWA operator to replace the ETàHLWA operator,which indicates that the method proposed in this paper is of universality and?exibility.

In this paper we do not make any conclusion about the deter-mining method of the linguistic(or2-tuple linguistic)weighted vector correlating with2-tuple linguistic hybrid arithmetic aggre-gation operators and effectively determining the expert weights in the form of the linguistic or2-tuples,which will be investigated in the near future.In addition,2-tuple linguistic hybrid geometric aggregation operators are also worthy of consideration for future research.

Acknowledgments

This work was partially supported by the National Natural Sci-ence Foundation of China(Nos.71061006,61263018,71171055

S.-P.Wan/Knowledge-Based Systems45(2013)31–4039

and70871117),the Program for New Century Excellent Talents in University(the Ministry of Education of China,NCET-10-0020),the Specialized Research Fund for the Doctoral Program of Higher Edu-cation of China(No.20113514110009),the Humanities Social Sci-ence Programming Project of Ministry of Education of China(No. 09YGC630107),the Natural Science Foundation of Jiangxi Province of China(No.20114BAB201012)and the Science and Technology Project of Jiangxi province educational department of China(Nos. GJJ12265and GJJ12740)and the Excellent Young Academic Talent Support Program of Jiangxi University of Finance and Economics. References

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