Page 81 - DCAP603_DATAWARE_HOUSING_AND_DATAMINING
P. 81

Unit 4: Data Mining Classification




                                                                                                notes
                        figure 4.6: transformation of a Decision tree into Decision rules

















          A rule can be “pruned” by removing any condition in its antecedent that does not improve the
          estimated accuracy of the rule. For each class, rules within a class may then be ranked according
          to their estimated accuracy. Since it is possible that a given test sample will not satisfy any rule
          antecedent, a default rule assigning the majority class is typically added to the resulting rule
          set.

          4.8 neural network based algorithms


          Artificial Neural Network

          An artificial neural network is a system based on the operation of biological neural networks,
          in  other  words,  is  an  emulation  of  biological  neural  system.  Why  would  be  necessary  the
          implementation of artificial neural networks? Although computing these days is truly advanced,
          there are certain tasks that a program made for a common microprocessor is unable to perform;
          even so a software implementation of a neural network can be made with their advantages and
          disadvantages.

          Advantages of Neural Network

          The advantages of neural network are:
          1.   A neural network can perform tasks that a linear program can not.

          2.   When an element of the neural network fails, it can continue without any problem by their
               parallel nature.
          3.   A neural network learns and does not need to be reprogrammed.
          4.   It can be implemented in any application.

          5.   It can be implemented without any problem.

          Disadvantages of Neural Network

          The disadvantages of neural network are:
          1.   The neural network needs training to operate.
          2.   The architecture of a neural network is different from the architecture of microprocessors
               therefore needs to be emulated.
          3.   Requires high processing time for large neural networks.





                                           LoveLy professionaL university                                    75
   76   77   78   79   80   81   82   83   84   85   86