ArticlePDF Available

A comparative analysis of multi-criteria decision-making methods

Authors:

Abstract

In this work, we empirically compare the rankings produced by several multi-criteria decision-making methods. We analyzed multi-MOORA, TOPSIS and three different settings for VIKOR. Using decision matrices with different number of alternatives and criteria, we compared the rankings produced using the Spearman’s correlation coefficient index. Our results showed that VIKOR could fail to obtain a ranking due to the failure of certain calculations. The rankings produced by TOPSIS and multi-MOORA were very similar, while the rankings produced by the different VIKOR variants showed a great variability.
Prog Artif Intell
DOI 10.1007/s13748-016-0093-1
REGULAR PAPER
A comparative analysis of multi-criteria decision-making methods
Blanca Ceballos1·María Teresa Lamata1·David A. Pelta1
Received: 20 January 2016 / Accepted: 4 April 2016
© Springer-Verlag Berlin Heidelberg 2016
Abstract In this work, we empirically compare the rank-
ings produced by several multi-criteria decision-making
methods. We analyzed multi-MOORA, TOPSIS and three
different settings for VIKOR. Using decision matrices with
different number of alternatives and criteria, we compared
the rankings produced using the Spearman’s correlation
coefficient index. Our results showed that VIKOR could
fail to obtain a ranking due to the failure of certain cal-
culations. The rankings produced by TOPSIS and multi-
MOORA were very similar, while the rankings produced
by the different VIKOR variants showed a great variabil-
ity.
Keywords TOPSIS ·VIKOR ·Multi-MOORA ·Rankings
comparison
1 Introduction
Multi-criteria decision-making (MCDM) methods are math-
ematical models that help to take decisions in scenarios where
the possible alternatives are evaluated over multiple conflict-
ing criteria.
BDavid A. Pelta
dpelta@decsai.ugr.es
Blanca Ceballos
bceballos@decsai.ugr.es
María Teresa Lamata
mtl@decsai.ugr.es
1Department of Computer Science and Artificial Intelligence,
University of Granada, 18014 Granada, Spain
The application areas of these methods are huge [8].
Examples can be found in supplier selection [18], techni-
cal evaluation of tenderers [10], evaluation of service quality
[9] or in renewable energy [1].
When facing a specific MCDM problem, there are no
clear guidelines on which MCDM method should be used
to solve it. This issue is controversial and it has been
studied in the literature since many decades ago [15
17,19]. It is true that depending on the MCDM method
applied, the solution could be different, specially when
the alternatives are very similar. Therefore, we seek to
do a comparative analysis among some MCDM meth-
ods, in order to better understand their similarities and
differences. The long-term goal is to have guidelines to sup-
port the decision-maker in the selection of which MCDM
method to apply. We consider this work a step towards such
goal.
There are many MCDM methods in the literature, as
PROMETHEE [3,4], AHP [14], ELECTRE [13], etc. In
this work, we focus on multi-MOORA [2,5], TOPSIS [7]
and VIKOR [11,12]. Multi-MOORA applies aggregation
operators, while TOPSIS and VIKOR operates calculating
distances to “ideal” or “reference” points. We selected these
methods for comparison because they have the same input
and all of them rely on a normalization procedure.
The comparison among methods is done over a set of
randomly generated decision matrices, as in [19] and then the
ranking “agreement” between pairs of methods is assessed
through the Spearman’s correlation coefficient.
The remainder of this paper is organized as follows. Sec-
tion 2provides a brief overview on what is an MCDM
problem, and describes the basic calculations of multi-
MOORA, TOPSIS and VIKOR. Section 3describes the
experimental framework and the results of the experiments.
Finally, Sect. 4is devoted to conclusions.
123
Prog Artif Intell
2 Multi-criteria decision-making problem and
methods
An MCDM problem [15] is composed by a finite set of alter-
natives represented as A={Ai|i=1,2,...,m},mbeing
the number of the alternatives. The alternatives are evalu-
ated according to certain criteria, denoted as C={Cj|j=
1,2,...,n}, where nis the number of the criteria. The criteria
can have different domains, and may represent a cost (which
is desirable to minimize) or a benefit (desirable to maximize).
In addition, each criterion is assigned an importance weight,
represented as W={wj|j=1,2,...,n}. These weights
are normalized to add up to one, i.e., n
j=1wj=1.
This information is organized in a decision matrix (Mm×n)
as in Table 1, where each element xij represents the value
of the alternative Aiwith respect to the criterion Cj.The
matrix Mand the vector of weights W={w1,w
2,...,w
n}
are the fundamental inputs for the MCDM methods that we
will consider here.
2.1 TOPSIS method
The TOPSIS method [7] evaluates the alternatives in terms
of their distance to the so-called “positive” and “negative”
ideal solution. TOPSIS is composed by the following steps:
Step 1 Normalize the decision matrix replacing every xij
by nij using the following formula:
nij =xij
m
j=1(xij)2
,(1)
where i=1,2,...,mand j=1,2,...,n.
Step 2 Calculate the weighted normalized values as vij =
wjnij, where wjcorrespond to the weight of the jth cri-
terion, i=1,2,...,mand j=1,2,...,n.
Step 3 Calculate the positive ideal solution (PIS), A+, and
the negative ideal solution (NIS), A, as follows:
(PIS)=A+={v+
1,v
+
2,...,v
+
j,...,v
+
n},
(NIS)=A={v
1,v
2,...,v
j,...,v
n},(2)
where v+
j=maxi(vij)and v
j=mini(vij)if the jth crite-
rion is benefit; and v+
j=mini(vij)and v
j=maxi(vij)if
the jth criterion is cost, i=1,2,...,mand j=1,2,...,n.
Table 1 Decision matrix of an
MCDM problem MCDM C1C2··· Cn
A1x11 x12 ··· x1n
A2x21 x22 ··· x2n
··· ··· ··· xij ···
Amxm1xm2··· xmn
Step 4 Calculate the distances from every alternative to
the ideal solutions, d+
ibeing the distance to A+, and d
ithe
distance to Aas following:
d+
i=
n
j=1
(vij v+
j)2
1/2
,
d
i=
n
j=1
(vij v
j)2
1/2
,(3)
which correspond to the m-dimensional Euclidean distance
and i=1,2,...,m.
Step 5 Calculate the relative closeness to both ideal solu-
tions as following:
Ri=d
i
d+
i+d
i
,(4)
where i=1,2,...,m.If Ri=0, then d
i=0 means that it
is the worst possible case. On the other hand, if Ri= 1, then
d+
i= 0 means that it is the best possible case. In general,
0Ri1.
Step 6 Rank the alternatives according to Riin descending
order. The best alternative is the one with the highest Ri.
2.2 VIKOR method
The VIKOR method [11] is, as TOPSIS method, also based
in the idea of the distances to “ideal solutions”. However,
some differences exist between both methods, as stated in
[12].
VIKOR method follows these steps:
Step 1 Determine the best f
jand worst f
jvalues of
each criterion as f
j=maxi(xij)and f
j=mini(xij),if
the jth criterion is benefit, and as f
j=mini(xij)and f
j=
maxi(xij)if the jth criterion is cost, i=1,2,...,mand
j=1,2,...,n.
Step 2 Normalize the xij values as follows:
nij =
f
jxij
f
jf
j
,(5)
where i=1,2,...,mand j=1,2,...,n.
Step 3 Calculate the values Siand Ri,i=1,2,...,m
and j=1,2,...,n:
Si=
n
j=1
wjnij,(6)
Ri=max
jwjnij(7)
123
Prog Artif Intell
Step 4 Calculate Qias follows:
Qi=v(SiS)
(SS)+(1v) (RiR)
(RR),(8)
where S=mini(Si),S=maxi(Si),R=mini(Ri),
R=maxi(Ri), and v[0,1]. Parameter vbalances the
relative importance of indexes Sand R.
Step 5 Sort Qin increasing order. The best-ranked alter-
native is the one with the lowest value of Q.
Step 6 Compromise solution: the so-called compromise
solution is the alternative awhich is the best ranked accord-
ing to Q(minimum) if the following two conditions are
satisfied:
Condition 1: Acceptable advantage.Q(a)Q(a)
DQ where a is the second best alternative according to
Qand DQ =1/(m1)(mis the number of alternatives).
Condition 2: Acceptable stability in decision-making.
Alternative amust be also the best ranked according
to Sand/or R(the alternative with the lowest value).
If one of the conditions is not satisfied, then a set of com-
promise solutions is proposed, which consists of:
The alternatives aand a if condition 1 is true and con-
dition 2 is false, or
The set of alternatives a,a,...,a(p)if condition 1 is
false; pbeing the position in the ranking of the alternative
a(p)verifying Q(a(p))Q(a)<DQ.
The best alternative, ranked by Q, is the one with the
minimum value of Q. The compromise ranking result is the
compromise ranking list of the alternatives with the “advan-
tage rate”.
2.3 Multi-MOORA method
Multi-MOORA constructs a ranking departing from three
calculations: the “Ratio System”, the “Reference Point” and
the “Full Multiplicative Form of Multiple Objectives” [5].
2.3.1 Ratio system
The first step is the normalization of the decision matrix.
Normalization is done according to Eq. 1(as in TOPSIS)
and the values are denoted as nij. Then, the ratio y
iof every
alternative is calculated as follows:
y
i=
g
j=1
nij wj
n
j=g+1
nij wj,(9)
where i=1,2,...,m,j=1,2,...,gare the benefit cri-
teria and j=g+1,2,...,mare the cost criteria. A higher
ratio y
iimplies a better ranking of the alternative.
2.3.2 Reference point
Initially, a reference point rjis calculated using the normal-
ized values and the weights. It is defined as rj=max j(nij
wj)if Cjis a benefit criteria, and as rj=min j(nij wj)
if Cjis a cost criteria. Then, every alternative is assigned a
value using the following metric:
min
i(max
j|rjnij wj|)(10)
The lower the value, the better the alternative is.
2.3.3 Full multiplicative form
An additional value Uiis calculated for every alternative:
Ui=g
j=1nwj
ij
n
j=g+1nwj
ij
,(11)
where i=1,2,...,m,j=1,2,...,gare the benefit crite-
ria and j=g+1,2,...,mare the cost criteria. Finally, the
best-ranked alternative according to the full multiplicative
form is the one that has the highest value of U.
In order to construct the final ranking, multi-MOORA cal-
culates a “summary of rankings” from the Ratio System,
Reference Point and Full Multiplicative Form by applying
the “Theory of Dominance” [6].
3 Experiments and results
3.1 Methodology
Our experiments departs from a set of randomly generated
MCDM problems (i.e., decision matrices). These matrices
were generated according to the procedure described in [19],
where the following parameters were used:
1. Number of criteria:n∈{5,10,15,20}.
2. Number of alternatives:m∈{3,5,7,9}.
3. Values of the alternatives:xij: randomly generated from
a uniform distribution in [0.01,...,1].
4. Criteria Weights: all of them are considered equally
important, thus wi=1/n.
5. Number of replications: we have generated 100 matrices
for each combination of mand n, t hus producing 4 ×4×
100 =1600 MCDM problems.
6. Methods: five methods are considered: TOPSIS, multi-
MOORA (MM) and three different parametrization of
VIKOR using v={0,0.5,1}(named as VIKOR0,
VIKOR0.5,VIKOR
1). When using VIKOR, we just take
123
Prog Artif Intell
the ranking generated with the Qindex, without consid-
ering the conditions of the “Compromise solution”, since
these are strong conditions (hard to meet) for the number
of alternatives in our experiments.
Every MCDM problem is solved using every method, giv-
ing a total of 8000 rankings.
Then, we measure the agreement between every pair of
rankings (one from each method) using the Spearman’s cor-
relation coefficient (ρ). An index value closer to 1 indicates a
high level of agreement (a “1” is obtained if the rankings are
equal). If the index is close to 0, then there is no agreement
between the rankings. Finally, if the index is close to 1, the
rankings are almost inverted.
For every combination of number of alternatives and cri-
teria, we analyze the results in terms of the average values of
ρover the corresponding 100 MCDM problems.
The analysis of results is separated in three parts. The
first part focuses on a problem affecting two variants of the
VIKOR method (VIKOR0and VIKOR0.5). The second part
provides a comparison of the methods on those cases where
VIKOR variants worked. Finally, in the third part, we com-
pare multi-Moora, TOPSIS and VIKOR1over the whole set
of problems.
3.2 A problem concerning the VIKOR method
We have observed that on some MCDM problems, VIKOR0
and VIKOR0.5failed to produce a ranking. This failure does
not appear with VIKOR1.
The reason lies at the core of the Rcalculation performed
in VIKOR (Eq. 7). In some problems, we observed that all
the alternatives have the same Rivalue. As a consequence
R=Rand the calculation of the Q(Eq. 8) index becomes
indeterminate for any v= 1. Potentially, the same situation
may occur with the Sivalues, but this never happened in our
experiment.
Table 2shows, for every combination of alternatives and
criteria, the percentage of problems solved by VIKOR0
and VIKOR0.5. Increasing the number of criteria, led to a
decrease in the percentage of problems solved (see the table
by rows). Also, if the number of criteria is fixed (reading the
Table 2 Percentage of problems solved (out of 100) by VIKOR0and
VIKOR0.5
Alternatives (m) Number of criteria (n)(%)
5 101520
332430
59447122
7 100 86 56 28
9 100 98 88 56
3579
0
25
50
75
100
Percentage
Number of alternatives
Percentage of solutions in VIKOR
Criteria
5
10
15
20
Fig. 1 Percentage of problems solved (out of 100) by VIKOR0and
VIKOR0.5
table by columns), the problem becomes “more solvable”
as the number of alternatives increases. For example, when
n=5, the percentage of problems solved raised from 32 %
when m=3 to 100 % when m=7 and m=9. Just in these
last combinations (n=5,m={7,9}), VIKOR is able to
provide a ranking for all the MCDM problems available.
Figure 1graphically shows the results of Table 2.Itcan
be observed that the rate of problems solved according to the
number of criteria varies in terms of the number of alterna-
tives available. When having n=20 criteria, the decision
problem should have much more than m=9 alternatives to
produce results. However, when n=5, it is almost enough
to have just m=5 alternatives to produce a ranking when
the MCDM problems are generated as we did. In general, the
percentage of problems solved increases with the number of
the alternatives available.
3.3 First comparison: all methods over a subset of
problems
Now, we will show an all-against-all comparison of the meth-
ods restricted to the cases where VIKOR0and VIKOR0.5
solved more than 80 % of the problems. These six cases
are n=5,m={5,7,9};n=10,m={7,9}and
n=15,m=9. Recall that we had tested 100 problems
in every case. The global results are shown in Table 3, where
the average values of ρ(over 600 MCDM problems) between
every pair of methods is shown.
On average, the agreement of the rankings produced by
TOPSIS and VIKOR1, and TOPSIS with multi-MOORA is
123
Prog Artif Intell
Table 3 Mean of ρover 600 MCDM problems (considering n=
5,m={5,7,9};n=10,m={7,9}and n=15,m=9)
Methods Mean ρ
TOPSIS–VIKOR10.88
TOPSIS–MM 0.87
VIKOR1–VIKOR0.50.83
VIKOR1–MM 0.82
VIKOR0.5–MM 0.78
VIKOR0.5–TOPSIS 0.75
VIKOR0–VIKOR0.50.61
VIKOR0–MM 0.44
VIKOR0–VIKOR10.35
VIKOR0–TOPSIS 0.33
MM multi-MOORA
VIKOR1−TOPSIS
VIKOR1−VIKOR0.5
MM−TOPSIS
MM−VIKOR0.5
MM−VIKOR1
VIKOR0.5−TOPSIS
VIKOR0−VIKOR0.5
VIKOR0−MM
VIKOR0−VIKOR1
VIKOR0−TOPSIS
0.25
0.5
0.75
1
Mean of ρ
Methods
5 Criteria
Alternatives
5
7
9
Fig. 2 Mean of ρfor 5 criteria and m={5,7,9}.MM multi-MOORA
very high (ρ0.87). Less similar rankings are produced
by VIKOR0and TOPSIS (ρ=0.33). Moreover, as the last
four rows correspond to VIKOR0, we can say that this method
produced rankings that shows very little similarity with those
produced by other methods. A similar observation can be
done regarding VIKOR0.5.
If we split the analysis in terms of the problem size, we
obtain the results depicted in Figs. 2,3and 4. Figures show
the mean of ρfor every pair of methods. Figure 2shows
the case for 5 criteria and different number of alternatives
(methods are sorted according with the results when m=9).
Figure 3considers 10 criteria and m={7,9}(methods are
also sorted according with the results when m=9). Finally,
VIKOR1−TOPSIS
MM−TOPSIS
VIKOR1−VIKOR0.5
MM−VIKOR1
MM−VIKOR0.5
VIKOR0.5−TOPSIS
VIKOR0−VIKOR0.5
VIKOR0−MM
VIKOR0−VIKOR1
VIKOR0−TOPSIS
0.25
0.5
0.75
1
Mean of ρ
Methods
10 Criteria
0.85 0.87
0.76
0.83
0.69 0.66
0.30
0.24 0.21
0.55
0.89 0.86 0.86 0.82 0.80 0.78
0.34
0.24 0.23
0.50
Alternatives
7
9
Fig. 3 Mean of ρfor 10 criteria and m={7,9}.MM multi-MOORA
VIKOR1−TOPSIS
MM−TOPSIS
MM−VIKOR1
VIKOR1−VIKOR0.5
MM−VIKOR0.5
VIKOR0.5−TOPSIS
VIKOR0−VIKOR0.5
VIKOR0−MM
VIKOR0−VIKOR1
VIKOR0−TOPSIS
0.25
0.5
0.75
1
Mean of ρ
Methods
15 Criteria
0.89 0.88 0.86 0.82
0.76 0.73
0.21 0.20
0.45
0.27
Fig. 4 Mean of ρfor 15 criteria and m=9. MM multi-MOORA
Fig. 4corresponds to n=15,m=9. The corresponding
values for Fig. 2are shown in Table 4.
The similarities among methods when considering the
problem sizes are quite similar to those shown in the global
analysis (Table 3). This fact can be checked seeing the order
of the methods in the X axis of the plots in Figs. 2,3and 4.In
addition, we can mention that the mean of ρis higher when
the number of alternatives is increased.
123
Prog Artif Intell
Table 4 Mean of ρfor MCDM problems with 5 criteria
Methods Alternatives (m)
579
VIKOR1–TOPSIS 0.79 0.88 0.91
VIKOR1–VIKOR0.50.80 0.84 0.89
MM–TOPSIS 0.87 0.86 0.88
MM–VIKOR0.50.73 0.82 0.87
MM–VIKOR10.78 0.81 0.85
VIKOR0.5–TOPSIS 0.67 0.77 0.85
VIKOR0–VIKOR0.50.67 0.72 0.74
VIKOR0–MM 0.47 0.58 0.64
VIKOR0–VIKOR10.39 0.46 0.53
VIKOR0–TOPSIS 0.36 0.45 0.52
Table is sorted according to m=9
MM multi-MOORA
A fact somehow “surprising” is the influence of the vvalue
in the output of VIKOR method with respect to TOPSIS.
When considering v=1(VIKOR
1), the output of the meth-
ods are almost similar. However, when v=0(VIKOR
0), the
outputs produced are quite different. In other words, VIKOR
shows a wide range of behaviors depending on a single para-
meter that makes it to behave or not like TOPSIS. To the
best of our knowledge, there are no guidelines to set up such
value when facing a new problem, so it is hard to imagine
how such value should be defined.
It should also be highlighted that TOPSIS and multi-
MOORA show a high mean value of ρ, stating that their
outputs are quite similar.
3.4 Second comparison: a subset of methods over all the
problems
In this subsection, we provide an all-against-all compari-
son of multi-MOORA, TOPSIS and VIKOR with v=1
(VIKOR1) over all the test problems considered (1600 dif-
ferent decision matrices).
Table 5shows the mean of ρfor every pair of methods, and
for all combinations of number of criteria and alternatives.
The values are also shown as plots in Fig. 5.
Focusing first on the comparison of multi-MOORA vs.
TOPSIS, we can observe a quite high level of agreement
between the rankings. The less similar case achieved an aver-
age of ρ=0.81 when m=3,n=10. As Fig. 5ashows,
such similarity is independent of the number of alternatives
and criteria.
The situation is different when multi-MOORA is com-
pared against VIKOR1. Now, the average ρranges from 0.58
(when m=3,n=10) to 0.85 (when m=9,n=5). From
Fig. 5b, it is clear that as the number of alternatives increased,
the outputs of the methods became more similar.
The comparison of TOPSIS vs. VIKOR1led to a similar
result. We should highlight the case where m=9 and n=5,
with an average ρ=0.91. This means that the outputs of
both methods are almost the same over the 100 tested cases.
Again, as Fig. 5c indicates, there is a clear tendency showing
that a higher number of alternatives implies a higher rank
similarity (independent of the number of criteria).
4 Conclusions
In this work, we performed a comparison of different MCDM
methods over 1600 randomly generated decision problems to
understand their similarities and differences in terms of the
rankings they produced.
The MCDM methods compared were: multi-MOORA,
TOPSIS and VIKOR, considering v=0, v=0.5 and
v=1, i.e., considering the rankings produced by S,Qand
R, respectively, in VIKOR.
From this comparison, two main points can be outlined:
the first one is relative to VIKOR method in particular, while
the second one is relative to multi-MOORA, TOPSIS and
VIKOR with v=1.
The first observation we did concerns the VIKOR method
in two aspects. Firstly, we point out that its output strongly
depends on the parameter v. The rankings produced when
using v={0.5,1}are quite similar. However, the use of
v=0 led to rankings that showed quite low similarities with
those from the other methods considered.
Secondly, when using VIKOR with v={0,0.5}we found
that the method failed to produce a ranking for many decision
Table 5 Mean of ρfor
all-against-all method’s
comparison
mn
MM vs. TOPSIS MM vs. VIKOR1TOPSIS vs. VIKOR1
5 10 15 20 5 10 15 20 5 10 15 20
3 0.88 0.81 0.87 0.88 0.64 0.58 0.67 0.71 0.61 0.51 0.61 0.68
5 0.87 0.86 0.84 0.86 0.78 0.79 0.77 0.76 0.79 0.78 0.78 0.80
7 0.86 0.87 0.85 0.85 0.81 0.83 0.84 0.83 0.88 0.85 0.86 0.87
9 0.88 0.86 0.88 0.84 0.85 0.82 0.86 0.83 0.91 0.89 0.89 0.88
MM multi-MOORA
123
Prog Artif Intell
3579
0.5 0.75 1
Mean of ρ
Number of alternatives
Multi−MOORA vs. TOPSIS
Criteria
5
10
15
20
3579
0.5 0.75 1
Mean of ρ
Number of alternatives
Multi−MOORA vs. VIKOR(v=1)
Criteria
5
10
15
20
(b)(a)
3579
1
5
7.
0
5.0
Mean of ρ
Number of alternatives
TOPSIS vs. VIKOR(v=1)
Criteria
5
10
15
20
(c)
Fig. 5 Mean of ρfor all-against-all method’s comparison
problems. In the most extreme case, VIKOR could not solved
any of the 100 problems with 3 alternatives and 20 criteria.
We may assume that this is a quite unrealistic situation, but it
also failed to provide a ranking in 44 problems (out of 100)
with 9 alternatives and 20 criteria. The problem relies on the
calculation of the Qindex, which is a convex combination of
two terms. One of them (R) produced a division by zero thus
leading to a indetermination in the Qvalue. In such cases,
VIKOR will fail for any v= 1. In other words, just one
possible value for vis “safe”.
The second observation address the results of the compar-
ison among multi-MOORA, TOPSIS and VIKOR1. Multi-
MOORA and TOPSIS obtained very similar results (their
rankings are almost the same), being the lowest value
of ρ0.81. A high level of similarity was obtained inde-
pendently of the number of criteria/alternatives consid-
ered.
The similarity of multi-MOORA with VIKOR1, and
VIKOR1with TOPSIS is not as high, but it clearly increased
as more alternatives are available. In both cases, the number
123
Prog Artif Intell
of criteria showed a quite minor influence on the similarity
values.
In short, our conclusions are in two lines: (1) if the problem
will be solved using several methods, then the user should not
choose simultaneously multi-MOORA and TOPSIS; and (2)
VIKOR’s ranking is very sensitive to the parameter v, thus it
should be carefully defined.
Acknowledgments Authors acknowledge support through projects
TIN2014-55024-P and P11-TIC-8001 from the Spanish Ministry of
Economy and Competitiveness, and Consejería de Economía, Inno-
vación y Ciencia, Junta de Andalucía (both including FEDER funds),
respectively. B. Ceballos enjoys a training Grant research staff under
project TIN2011-27696-C02-01 (Spanish Ministry of Economy and
Competitiveness).
References
1. Abu Taha, R., Daim, T.: Multi-criteria applications in renewable
energy analysis, a literature review. In: Daim, T., Oliver, T., Kim,
J. (eds.) Research and Technology Management in the Electricity
Industry: Methods, Tools and Case Studies, pp. 17–30. Springer,
London (2013)
2. Baležentis, T., Baležentis, A.: A survey on development and
applications of the multi-criteria decision making method MULTI-
MOORA. J. Multi-Criteria Decis. Anal. 21(3–4), 209–222 (2014)
3. Brans, J.P., Mareschal, B., Vincke, P.: Promethee: a new family
of outranking methods in multicriteria analysis. In: Operational
Research ’84, Proceedings of the Tenth International Conference,
pp. 477–490. Washington, DC (1984)
4. Brans, J.P., Vincke, Ph, Mareschal, B.: How to select and how
to rank projects: the Promethee method. Eur. J. Oper. Res. 24(2),
228–238 (1986)
5. Brauers, W.K.M., Zavadskas, E.K.: Project management by mul-
timoora as an instrument for transition economies. Technol. Econ.
Dev. Econ. 16(1), 5–24 (2010)
6. Brauers, Willem Karel M., Zavadskas, Edmundas Kazimieras:
Robustness of multimoora: a method for multi-objective optimiza-
tion. Informatica 23(1), 1–25 (2012)
7. Chen, S.J., Hwang, C.L., Hwang, F.P.: Fuzzy multiple attribute
decision making(methods and applications). Lecture Notes in Eco-
nomics and Mathematical Systems (1992)
8. Mardani, A., Jusoh, A., Zavadskas, E.K.: Fuzzy multiple criteria
decision-making techniques and applications: two decades review
from 1994 to 2014. Expert Syst. Appl. 42(8), 4126–4148 (2015)
9. Mardani, A., Jusoh, A., Zavadskas, E.K., Khalifah, Z., Nor,
K.M.D.: Application of multiple-criteria decision-making tech-
niques and approaches to evaluating of service quality: a systematic
review of the literature. J. Bus. Econ. Manage. 16(5), 1034–1068
(2015)
10. Mohamed, N.H., Lamsali, H., Sathyamoorthy, D.: Multi-criteria
decision making (mcdm) for technical evaluation of tenderers: a
review of methods employed. Defence S T Tech Bull 8(1), 90–102
(2015)
11. Opricovic, S.: Multicriteria Optimization of Civil Engineering Sys-
tems. Faculty of Civil Engineering, Belgrade (1998)
12. Opricovic, S., Tzeng, G.-H.: Compromise solution by MCDM
methods: a comparative analysis of VIKOR and TOPSIS. Eur. J.
Oper. Res. 156(2), 445–455 (2004)
13. Roy, B., Hugonnard, J.C.: Ranking of suburban line extension
projects on the Paris metro system by a multicriteria method.
Transp. Res. A: Gen. 16(4), 301–312 (1982)
14. Saaty, T.L.: The Analytic Hierarchy Process. McGraw-Hill, New
York (1980)
15. Triantaphyllou, E.: Multi-criteria decision making methods. In:
Multi-criteria Decision Making Methods: A Comparative Study,
pp. 5–21. Springer, New York (2000)
16. Triantaphyllou, E., Chi-Tun, L.: Development and evaluation of
five fuzzy multiattribute decision-making methods. Int. J. Approx-
imate Reasoning 14(4), 281–310 (1996)
17. Triantaphyllou, E., Mann, S.H.: An examination of the effective-
ness of multi-dimensional decision-making methods: a decision-
making paradox. Decis. Support Syst. 5(3), 303–312 (1989)
18. Yildiz, A., Yayla, A.Y.: Multi-criteria decision-making methods
for supplier selection: a literature review. S. Afr. J. Ind. Eng 26(2),
158–177 (2015)
19. Zanakis, S.H., Solomon, A., Wishart, N., Dublish, S.: Multi-
attribute decision making: a simulation comparison of select
methods. Eur. J. Oper. Res. 107(3), 507–529 (1998)
123
... In this context, the assistance of Multi-Criteria Decision Analysis (MCDA) methods becomes invaluable, facilitating the creation of decision-making models based on defined input data [2]. In the face of uncertainty prevalent in decision processes, where various methods within multi-criteria evaluations are utilized, examining how selecting techniques influence outcomes becomes a visible challenge [3]. Based on evaluation criteria, a decision matrix, and criterion weights, these methods offer a means to identify rational choices tailored to the decision-maker's requirements, effectively meeting the identified needs [4]. ...
... The main objective of the proposed programming package is to equip users with various methods that could be used to examine the sensitivity analysis of results obtained from the multi-criteria decision analysis evaluations. For this purpose, the package was built based on eight modules described as follows: 2. criteria: (1) Relevance identification [17], (2) Percentage modification [18], (3) Range modification, (4) Criteria removal [19], (5) Weights scenarios generation, (6) Random distribution 3. probabilistic: (1) Monte Carlo weights [20], (2) Perturbed matrix [21], (3) Perturbed weights [22] 4. ranking: (1) Ranking alteration [9], (2) Ranking demotion, (3) Ranking promotion [23], (4) Fuzzy ranking 5. compromise: (1) HQ compromise [24], (2) ICRA [25], (3) Borda [26], (4) Dominance directed graph [27], (5) Improved Borda [28], (6) Rank position [26] 6. graphs: (1) Heatmap, (2) Ranking promotion/demotion, (3) Preference distribution, (4) Rankings distribution, (5) Values distribution, (6) Weights barplot 7. calculate_preference: this module offers the possibility of performing multi-criteria decision analysis evaluation based on the input generated modified input data with functionalities provided in the programming package 8. validator: this module serves functionalities allowing for validating input data given by the user for all of the methods implemented within the library ...
... The main objective of the proposed programming package is to equip users with various methods that could be used to examine the sensitivity analysis of results obtained from the multi-criteria decision analysis evaluations. For this purpose, the package was built based on eight modules described as follows: 2. criteria: (1) Relevance identification [17], (2) Percentage modification [18], (3) Range modification, (4) Criteria removal [19], (5) Weights scenarios generation, (6) Random distribution 3. probabilistic: (1) Monte Carlo weights [20], (2) Perturbed matrix [21], (3) Perturbed weights [22] 4. ranking: (1) Ranking alteration [9], (2) Ranking demotion, (3) Ranking promotion [23], (4) Fuzzy ranking 5. compromise: (1) HQ compromise [24], (2) ICRA [25], (3) Borda [26], (4) Dominance directed graph [27], (5) Improved Borda [28], (6) Rank position [26] 6. graphs: (1) Heatmap, (2) Ranking promotion/demotion, (3) Preference distribution, (4) Rankings distribution, (5) Values distribution, (6) Weights barplot 7. calculate_preference: this module offers the possibility of performing multi-criteria decision analysis evaluation based on the input generated modified input data with functionalities provided in the programming package 8. validator: this module serves functionalities allowing for validating input data given by the user for all of the methods implemented within the library ...
Article
Full-text available
The presented programming package introduces an innovative tool for sensitivity analysis within MultiCriteria Decision Analysis (MCDA), offering a modular and flexible structure for versatile applications. The PySensMCDA package is developed in Python and ensures adaptability by adjusting the behavior of sensitivity analysis methods to the specific needs of users. Robust input data validation enhances reliability by minimizing errors. The versatility of the proposed package allows for both personal and research applications within the MCDA domain, making it an important contribution to enhancing the comprehensiveness of the assessment. The eight modules encompass a variety of sensitivity analysis approaches, including alternative modification, criteria weights adjustment, probabilistic approaches, ranking alterations, compromise solutions, preference calculations, graph visualizations, and data validation. The main aim is to equip decision-makers with predefined sensitivity analysis methods, thereby facilitating more comprehensive and detailed analyses in multi-criteria decision scenarios.
... It was used as a key indicator for overall assessment of the coherence of the rankings when different MCDM methods were used for the same decision task. Ceballos et al. [37] compared the rankings obtained from different six MCDM methods using the Spearman's correlation coefficients. Vakilipour et al. [38] used correlation and stability measures of the methods to compare the results obtained from different MCDM methods. ...
... The MRCC and MARD mainly reflect the features for comparing the performance of the MCDM methods, which were mentioned in the Refs. [35][36][37][38]. (2) The proposed correlation-based influence analysis, multiple regression modeling and grid search optimization methods are not only simple but also effective and practical methods for machining performance modeling and optimization. ...
Article
Full-text available
This paper proposes multiple performances optimization methodology for computer numerical controlled (CNC) machining based on Taguchi method, multi-criteria decision-making (MCDM) and multiple regression (MR) model. It consists of the following steps: (1) setting levels of process parameters and selecting suitable Taguchi orthogonal array (OA), (2) arranging the process parameters on the OA and measuring machining performance values at every trials, (3) calculating comprehensive performance (CP) by integrating the multiple performances using a reasonable MCDM, (4) developing MR model between the CP and the process parameters, (5) analyzing influence of the process parameters based on correlation analysis, and (6) determining the optimal process parameters using grid search method. The methodology was applied to analyze and determine the influence and optimal turning process parameters such as cutting speed (CS), feed rate (FR), cutting depth (CD), cutting environment (CE) and tool nose radius (NR) for optimizing four machining performances such as surface roughness (SR), cutting force (CF), tool life (TL) and power consumption (PC) in the high speed CNC turning of AISI P20 tool steel. As the result, the optimal values of the turning process parameters were determined as CS of 160 m/min, FR of 0.1 mm/r, CD of 0.2 mm, CE of cryogenic environment, and NR of 1.1 mm. The influence analysis and optimization results of the process parameters were compared with the results obtained from the Taguchi method. The proposed methodology could be widely applied to many practical machining process optimization problems in small medium enterprise (SME) or fabrication laboratory (FabLab).
... Several researchers have applied multi-criteria decision-making methods for choosing the optimum alternative when faced with a group of similar alternatives, based on multiple criteria or factors [16,17]. This process can be described as multi-criteria decision analysis. ...
Article
Full-text available
Sustainably selecting the best cutting fluid among alternatives, considering various weighted criteria or factors, is a complex problem encountered by machine operators in engineering workshops worldwide. The aim of this work is to utilize the Multi-attribute Utility Theory (MAUT) decision-making model for biodegradable cutting fluids selection in a machine shop. The objectives of the work include carrying out a step-by-step process of the MAUT method on biodegradable cutting fluid alternatives. Therefore, this study utilizes the MAUT decision-making method for selecting the best biodegradable cutting fluid among a set of five (5) alternatives namely soybean oil, palm oil, polyalphaolefin, trimethylpropane trioleate and polyethylene glycol. The cutting fluids were evaluated based on criteria such as heat dissipation, stability, lubrication and cost-effectiveness. From the results, Polyalphaolefin is the best alternative, ranking first according to the global utility scoring. Therefore, Polyalphaolefin had a global utility score of 0.688, followed by Polyethylene Glycol which had a score of 0.600, followed by Trimethylpropane Trioleate which had a score of 0.588, followed by Soybean Oil which had a score of 0.363 and finally, Palm Oil which had a score of 0.263. This study provides a procedure for implementing the MAUT method of decision-making for cutting fluids selection within engineering workshops for sustainable machining practices.
... Notably, the comparison of TOPSIS, fuzzy MOORA, and MOORA yields a correlation coefficient of 1, signifying identical ranking results from these three methods. The significance values for the remaining pairs of methods are all below 0.05, indicating a strong positive correlation in their ranking outcomes [75,76]. Similarly, the Pearson correlation result is all sig values are below 0.05, and the correlation values between pairs of methods exceed 0.8, demonstrating that the results of these ranking methods are related to each other [77]. ...
Article
Full-text available
Non-traditional security (NTS) threats have a vast and profound impact on many aspects of economic, political, social, and many other areas, especially supply chain finance (SCF), particularly in countries like Vietnam, which potentially affects the economic efficiency of businesses' supply chain financial , thereby affecting the general economy of the country and the world. In order to prevent and minimize the negative impacts caused by NTS threats to SCF, this study was conducted to identify NTS threats affecting SCF in Vietnam, at the same time calculate the weight of the impact level and find out the cause and effect relationship between them. Solution strategies are also proposed and ranked, thereby serving as a reference basis for relevant parties to choose appropriate response solutions. Due to the multi-criteria nature of NTS threats, the multiple criteria decision-making (MCDM) method is used in combination with the Z-number concept and Fuzzy set theory to approach the problem of certainty and increase the accuracy of study. The NTS threats are first identified through a literature review and then validated for suitability using the DELPHI technique (DELPHI). Suitable threats will be determined by relationship, weighted by Decision Making Trial And Evaluation Laboratory (DEMATEL) method. Proposed strategies are ranked using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method. The results indicate that there are 19 NTS factors affecting SCF in Vietnam, and the global economic downturn, pandemic and health crisis, financial crisis and cybersecurity risk are the four root cause factors with the most decisive influence. Businesses and concerns need to prioritize addressing these four threats because they not only have a strong impact but also entail many other threats. The two strategies considered to be the most effective are a sustainable practice and a risk-hedging strategy. Businesses, governments, and stakeholders also should pay attention to the macroeconomic environment, technology, and environment and build sustainable businesses, regularly monitoring economic fluctuations and creating plans to prevent risks.
... On the other hand, in the case of typically discrete and predefined alternatives of finite set MADM is utilized. Various MADM methods are utilized in the literature such as analytical hierarchy process (AHP) Ramkar and Yadav 2021;, technique for order preference by similarity to ideal solution (TOPSIS) (Ceballos et al. 2016;Goodarzi et al. 2019;Zhang et al. 2022), analytical network process (ANP) (Nasiri Khiavi et al. 2023;Rashidi Shikhteymour et al. 2023;Sahraei et al. 2023), best-worst method (BWM) (Nasiri Khiavi et al. 2023;Sahraei et al. 2023), data envelopment analysis (DEA), stepwise weight assessment ratio analysis (SWARA), complex proportional assessment (COPRAS) (Sahraei et al. 2023), Multi Influencing Factor (MIF) (Hani et al. 2023;Rane et al. 2023) etc. to address the variety of decision-making problems. ...
Article
Full-text available
The comparison of the discrete and finite set of predefined alternatives requires a simple, effective, and reliable Multi-Attribute Decision-Making (MADM) method. This paper shows an application of a simple and effective MADM technique named the Best Holistic Adaptable Ranking of Attributes Technique (BHARAT) to find the best-performing ensemble prediction system (EPS) in issuing flood warnings in the study area. The three well-behaved EPSs, European Centre for Medium-Range Weather Forecast (ECMWF), the National Centre for Medium-Range Weather Forecasting (NCMRWF), and the United Kingdom Meteorological Office (UKMO) for 1-day and 5-day leadtime were considered in the study. The EPSs are considered as the alternatives and the evaluation metrics of the precipitation forecasts and hydrologic forecasts are considered as the factors (attributes) in the BHARAT method. The evaluation is categorized into three factors, (1) performance metrics for the evaluation of precipitation forecasts, (2) evaluation metrics based on the hydrological model performance, and (3) threshold-based evaluation metrics of the hydrologic forecasts. These factors are further divided into eleven sub-factors. The BHARAT method includes assigning numerical weights by the decision maker, which are directly multiplied with the normalized values based on the “best” attribute value of an alternative and summed up to get the best-performing alternative. The results of the BHARAT method showed that the total scores of the alternative NCMRWF are 0.976 and 0.916 for 1-day and 5-day leadtime. Thus, the NCMRWF EPS is found to be the best performing in both the leadtime for issuing the flood warning in the Vishwamitri River basin. At the global scale, BHARAT can be applied in similar studies of decision-making with variable attributes in the fields of hydrology to find the best alternative.
... Multi-criteria decision analysis (MCDA) are mathematical procedures that allows to take a decision among different scenarios through the evaluation of multiple conflicting criteria (Ceballos et al., 2016). Different approaches can be taken into consideration, being one to consider equal importance to all the S aspects (environment, society and economy). ...
... In the literature, Analytical Hierarchical Process (AHP) and Multi-Criteria Analysis (MCA) are the two major integrative tools used for decision-making and analyzing complex issues involving multiple criteria (Dyer, 1990;Bana e Costa et al., 1997;Triantaphyllou, 2000;Beinat, 2001;Dodgson et al., 2009;Huang et al., 2011;Van Ierland et al., 2013;Mu & Pereyra-Rojas, 2017;Lamata & Pelta, 2017;Asadabadi et al., 2019;Dean, 2021;Huang et al., 2023;Madanchian, 2023;Cheng et al., 2024). When it comes to analyzing respondent perceptions, the two methods have been found to be appropriate, particularly when dealing with complex decision problems involving multiple criteria, depending on the context and goals of the analysis. ...
Article
Full-text available
Urbanization is a major source of anthropogenic effects on climate change (CC) and has attracted substantial research interest. However, previous studies assessing the CC knowledge of urban dwellers have not utilized models that enable a quantitative, integrated assessment of knowledge levels. This research aims to bridge this gap by developing and operationalizing a CC knowledge level (CCKL) assessment model to study indigenous households’ knowledge levels in Abuja, Nigeria, with the aim of investigating the potential of traditional ecological knowledge (TEK) in enhancing our comprehension of the ecological consequences of urbanization. This is to explore how TEK contributes to the understanding of the impact of urbanization on local ecological conditions among the indigenous households in the area. Through the collection of data on 25 CC items from 514 households, the study computed CCKL values that enabled a quantitative evaluation of households' awareness levels regarding the effects of urbanization on their environment. The findings showed some notable variations exist across towns, attributed to housing, infrastructural, and dwelling disparities. Over 80% of the respondents aged 40–80 years suggest long-term residency, influencing ecological knowledge. Over 90% of household heads being male aligns with West African norms. Marriage rates are high, and smaller household sizes deviate from the typical African setting, possibly due to urbanization trends. The TEK assessment reveals households' reasonable understanding of climate change, especially regarding temperature, rainfall, surface water, and land conditions. Yet, knowledge gaps exist, particularly in complex areas like climate-induced biodiversity loss and groundwater changes. In addition to a lack of formal education, limited to primary and secondary levels for most, income levels indicate economic vulnerabilities. Households exhibit resilience to urbanization-induced ecological changes, employing adaptive strategies. However, perceptions of urbanization's impact on groundwater and biodiversity diverge from scientific knowledge, indicating understanding gaps. The CCKL assessment model, though integrated and quantifiable, faces challenges such as subjectivity and oversimplification. Validation efforts, including calibration, pilot testing, and expert reviews, enhance the model's reliability.
Article
Full-text available
Purpose: The objective of this study is to identify the strategic factors determining the level of sustainability in healthcare and to examine their relative priority levels. Methodology: The Analytic Hierarchy Process (AHP) method, a quantitative multi-criteria decision-making technique, was employed. Factors were identified through a review of relevant literature. Experts assessed the importance of each factor on a scale of 1 to 9, employing pairwise comparison forms. The panel of experts comprised four representatives from hospitals awarded the Leadership in Energy and Environmental Design (LEED) certification and four academics in health management. The data which was collected from experts were analyzed according to the AHP method’s procedural steps, resulting in the determination of the factors' importance levels. Findings: Factors determining the level of sustainability in healthcare were categorized into three primary groups; social, economic, and environmental. The economic factors emerged as the most significant, receiving a score of 0.4433. The rankings varied according to the participant groups; representatives from the sector identified economic factors as the most critical, whereas academics ranked environmental factors to be of paramount importance. Originality: This study possesses unique value, as it explores the multidimensional concept of sustainability focusing on its specific implications in healthcare services and provides a general framework for measuring the efficiency and effectiveness in this field. Keywords: Sustainability, Healthcare Services, Analytic Hierarchy Process, Health Management.
Article
Full-text available
The main purpose of this paper is to present a systematic review of multiplecriteria decision-making (MCDM) techniques used in the assessment of service quality. This study reviewed a total of 79 articles from 51 journals, published from 2001 to 2015. Articles were classified into 10 application areas and scopes. Furthermore, articles were categorised based on an author, year, application area, the nationality of the author, technique, a number of criteria, research purpose, gap and research problem, results and outcome. The best criteria were determined in each article. The results of this study revealed that more papers on MCDM were published in 2011 than in any other year. Integrated techniques, analytic hierarchy process (AHP) and fuzzy AHP methods, were ranked as first and second methods in use, respectively. Finally, the airline industry was ranked as the first application area, in which previous studies applied MCDM techniques for the evaluation of the service quality. This research contributes to the existing literature on the service quality and MCDM. The research outputs are valuable to academics scholars and leaders of organisations and industries in the field of service quality evaluation.
Article
Full-text available
A firm’s multi-criteria decision-making (MCDM) process is important because of its need to select and work with various suppliers. The process identifies the problems associated with selecting the supplier, , determining convenient criteria, expressing interactions clearly, and usage. These are all suitable methods for finding a solution to these MCDM problems. Considering more than one criterion (and even the sub-criteria of these criteria) during supplier selection makes the selection uncertain. Conventional methods cannot generate a realistic solution to the problem. Using MCDM methods considerably simplifies solving the problem, and enables decision-makers to make better decisions. In this study, a literature review was performed on MCDM methods used between 2001 and 2014 for the supplier selection problem. MCDM methods used in supplier selection are categorised into three main methods, and a summary table of the reviewed studies is presented.
Book
Full-text available
With the continuing proliferation of decision methods and their variants, it is important to have an understanding of their comparative value. Each of the methods uses numeric techniques to help decision makers choose among a discrete set of alternative decisions. This is achieved on the basis of the impact of the alternatives on certain criteria and thereby on the overall utility of the decision maker(s). The difficulty that always occurs when trying to compare decision methods and choose the best one is that a paradox is reached, i.e., What decision-making method should be used to choose the best decision-making method? This problem is examined in Chapter 9.
Article
Full-text available
Multi-criteria decision making (MCDM) is an area that is often discussed in operations research (OR). It is able to handle problems involving multiple criteria, and produce meaningful and quality decision making, especially in selecting the best alternative. This paper is aimed at reviewing the applications of MCDM for technical evaluation of tenderers. It identifies the problems that often occur in technical evaluation of tenderers. The MCDM techniques that have been employed to address these problems are then discussed, along with their benefits and limitations. Based on the review conducted, it can be suggested that analytical hierarchy process (AHP) is the most practical MCDM method for technical evaluation of tenderers, as it provides a fair and open process of assessment by taking into consideration the evaluators involved to avoid the issue of bias, and can be carried out with simplicity and transparency. Nonetheless, studies on other MCDM methods should be further explored due to the limitations of AHP.
Article
Full-text available
MCDM is considered as a complex decision-making tool involving both quantitative and qualitative factors. In recent years, several fuzzy FMCDM tools have been suggested to choosing the optimal probably options. The purpose of this paper is to review systematically the applications and methodologies of the fuzzy multi decision-making (FMCDM) techniques. This study reviewed a total of 403 papers published from 1994 to 2014 in more than 150 peer reviewed journals (extracted from online databases such as ScienceDirect, Springer, Emerald, Wiley, ProQuest, and Taylor & Francis). According to experts’ opinions, these papers were grouped into four main fields: engineering, management and business, science, and technology. Furthermore, these papers were categorized based on authors, publication date, country of origin, methods, tools, and type of research (FMCDM utilizing research, FMCDM developing research, and FMCDM proposing research). The results of this study indicated that, in 2013, scholars have published papers more than other years. In addition, hybrid fuzzy MCDM in the integrated method and fuzzy AHP in the individual section were ranked as the first and second methods in use. Additionally, Taiwan was ranked as the first country that contributed to this survey, and engineering was ranked as the first field that has applied fuzzy DM tools and techniques.
Article
Full-text available
Multi-Objective Optimization takes care of different objectives with the objectives keep-ing their own units. The internal mechanical solution of a Ratio System, producing dimensionless numbers, is preferred. The ratio system creates the opportunity to use a second approach: a Refer-ence Point Theory, which uses the ratios of the ratio system. This overall theory is called MOORA (Multi-Objective Optimization by Ratio Analysis). The results are still more convincing if a Full Multiplicative Form is added forming MULTIMOORA. The control by three different approaches forms a guaranty for a solution being as non-subjective as possible. MULTIMOORA, tested after robustness, showed positive results.
Article
Energy impacts so many aspects of our lives. This makes it necessary to evaluate multiple aspects when we are evaluating energy alternatives. This chapter introduces us to a spectrum of tools for this evaluation.
Article
This is an overview of the Analytic Hierarchy Process (AHP). It illustrates three of the five methods of measurement of the subject in decision making. They are relative measurements, a) the distribution mode using normalization to allow for appropriate rank reversal, b) the ideal mode to allow for rank preservation and absolute measurement which utilizes intensities for the criteria used to rate alternatives, one at a time useful with expert knowledge. Two other modes of the AHP, which are feedback and the supermatrix and continuous comparisons in the context of integral equations, are briefly mentioned. The overview also includes the axioms of the AHP and a brief mention of the areas of application.