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Fuzzy MCDM for ranking the biofuels production pathways  325


                    n
                j    1, if the ith alternativehasbeen rankedat thetth place
                it                                                      (11.12)
               φ ¼   0, if the ith alternativehasnot been rankedat thetth place
                                               j
                                         j
                                        φ ¼ φ                           (11.13)
                                               it m m
                     j
                                                                            j
              where φ is the ranking matrix corresponding to the ( j)th criterion and φ it is
              the element in the ranking matrix corresponding to the ( j)th criterion.
                 Step 4: Weighted ranking matrix.
                 The weighted ranking matrix R can be obtained by Eq. (11.14) and the
              elements in the weighted ranking matrix can be calculated by Eqs. (11.15),
              (11.16).
                                            1  2 ⋯ m

                                       A 1 r 11 r 12 ⋯ r 1m
                                   R ¼ A 2 r 21 r 22 ⋯ r 2m             (11.14)
                                        ⋮   ⋮  ⋮   ⋮   ⋮
                                       A m r m1 r m2 ⋯ r mm
                                             n
                                            X
                                                 j
                                               φ ω j                    (11.15)
                                        r it ¼   it
                                            j¼1
                                           !
                             ω +2ω + ω   U    X ω +2ω + ω    U
                                    M
                                               n
                                                        M
                                                  L
                              L
                              j     j    j        j     j    j
                                            =                           (11.16)
                       ω j ¼
                                   4                   4
                                              j¼1
                 Step 5: Ranking the sequence of the alternatives.
                 Use the following linear 0–1 programming to rank the alternatives, and
              the solutions of this programming are the elements in the final ranking
              matrix Z, as shown in Eq. (11.21).If z it ¼1, it means that the (i)th alternative
              has been ranked at the (t)th place.
                                              m  m
                                             XX
                                                                        (11.17)
                                                    r it z it
                                     Max S ¼
                                             j¼1 t¼1
                    n
                     1, if the ith alternativehasbeen rankedat thetth place
                     0, if the ith alternativehasnot been rankedat thetth place
               z it ¼                                                   (11.18)
                                    m
                                   X
                                      z it ¼ 1, i ¼ 1,2,…,m             (11.19)
                                   t¼1
                                    m
                                   X
                                      z it ¼ 1, t ¼ 1,2,…,m             (11.20)
                                   i¼1
                                                                        (11.21)
                                        Z ¼ z it m m
                                            fg
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