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2. Probability and Random Process                                 81

                                    2
                                                  2 2
              M 45   = 1/    [((vector 4-c5) / (vector4 –c1) )  +
                                   2
                                                2 2
                              ((vector 4-c5) / (vector4–c2 )  +
                                   2
                                                 2 2
                              ((vector 4-c5) / (vector4 –c3 )  +
                                   2
                                                 2 2
                              ((vector 4-c5) / (vector4 –c4 )  +
                                                 2 2
                                   2
                              ((vector 4-c5) / (vector4 –c5 )  +
                                                 2 2
                                   2
                              ((vector 4-c5) / (vector4 –c6 ) ]

              Similarly other membership values are computed.

           Step 4:  Compute the sum of the squared difference between the previous
                  membership value and the current membership value. If the computed
                  value is not less than the threshold value go to step 2 to compute the
                  next set of centroids and followed by next set of membership values. If
                  the threshold value is less than the threshold value, stop the iteration.
                  Thus the centroids are obtained using fuzzy k-means algorithm. Using
                  the computed centroids, clustering can be obtained as described in the
                  section 3.
           4.2      Example
           The particular sets of  marks (data) are subjected to Fuzzy k-means
           algorithm. Final clusters along with clusters obtained at every iteration are
           displayed below.

































                           Figure 2-4. Illustration of Fuzzy K-means algorithm
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