Environmental Engineering Reference
In-Depth Information
Based on Saaty ( 1990 ) AHP has a built-in mechanism for input validation.
Also AHP, known for its flexibility and ability to decompose a decision problem
(Oztaysi 2014 ), is used to determine the weights of the evaluation factors and
criteria then these weights are later used in TOPSIS and GRA respectively.
The main idea of TOPSIS is that the best alternatives should have farthest dis-
tance from the negative ideal solution and the shortest distance from the positive
ideal solutions. TOPSIS method is agile and well suited to the problem of decision
making in regard to changes and number of alternatives and criteria. Also TOPSIS
can analyze both qualitative and quantitative criteria (Junior et al. 2014 ). Therefore
in this chapter, criteria selection procedure is based on TOPSIS technique and
required data are derived from purchase manager who is often experienced in sup-
plier selection of food industries. Candidate criteria rank based on evaluation fac-
tor which is aligned with company policy and goals.
In decision making process of supplier selection, the decision makers try to
gather as much information as possible through surveys, investigations, sam-
pling, etc. To reach the aspired decision obtaining all the information is impos-
sible; therefore decisions are usually made in uncertain process, i.e. without
complete information. This is where GRA, finds application in solving MCDM
problems (Oztaysi 2014 ; Zhang and Liu 2011 ). In comparison with conventional
evaluation methods, the GRA possesses several advantages: calculations are
simple, requires small samples, sample distribution is not needed as per prob-
ability theory, no confliction between subjective and objective data sets and it is
effective in dealing with distributed statistics (Deng 1989 ; Wu 2002 ; Goyal and
Grover 2012 ).
In many situations of real world, precise description is impossible; there-
fore approximations (or fuzziness) must be introduced. Fuzzy logic can trans-
form uncertain human knowledge into a mathematical formula (Zadeh 1965 ).
Combining fuzzy sets to decision making methods will lead to realistic results.
Subjective judgment of decision maker has encouraged application of group deci-
sion making which uses an expert team to make final decision. Finally fuzzy GRA
technique has been named for green supplier selection.
This chapter will support decision makers in developing methodology for
nominating, order ranking and choosing effective criteria and then selecting
green supplier. Criteria selection is based on evaluation factors which are
weighted by AHP and using TOPSIS analysis high ranked criteria collected for
GSS. Then high ranked criteria are weighted by AHP and suppliers ranked using
fuzzy GRA.
3 Methodology
The methodology proposed in this chapter, support the decision maker to find
criteria which is firstly adapted to company policy and then accomplish the
supplier selection procedure.
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