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CPS1915 Han G. et al.
            ranges from around 65% to 74% under all conditions for Model I and Model
            II (see Figure 4).






















             Figure 4. Prediction accuracy for Model I and Model II when n_h = 10, 20, 30,
               40, 50 and learning rate = (a) 2.0; (b) 0.5; (c) 0.1; (d) 0.05; I 0.01; (f) 0.005

            4.  Discussion and Conclusion
                The neural network is a highly complex system with various parameters as
            well as hyperparameter. In this research, neural network models with different
            activation functions in hidden layer were discussed. The results showed that
            the prediction accuracies for Model I and Model II with different hidden layer
            neurons and learning rates mainly ranges from 60% to 70%. Model II had a
            relatively  stable  prediction  performance compared  to Model  I.  Overall, the
            prediction power between Model I and Model II is not quite obvious. In other
            words, the comparison result is prone to be negative. However, the research
            result can still provide some intuitions on how the neural network works. Due
            to  the  limited  sample  number  and  input  features,  the  performance  of  the
            models we proposed was relatively poorer than the NN model proposed by
            More et al. (2014). Although the models we proposed have quite promising
            prediction  power,  there is  still  some  future  work  for  improvement  such as
            follows:
                (1)  The raw data was only split into training set and test set. The validation
                   dataset can provide an unbiased evaluation for the model to fit on the
                   training set while tuning the model’s hyperparameters. The split ratio
                   can be 60-20-20 or 70-15-15.
                (2)  Feature selection was not conducted in this research. Since the dataset
                   available  from  UCI  Machine  Learning  Repository  includes  20  input
                   features, while the raw dataset includes more than 100 features.





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