WEEK4：
This week I started learning about neural networks. I first introduced some new developments in brain research. I won’t show it here, let’s go directly to the topic.
Neural Network Overview:
Regarding neural networks, the tutorial gives the simplest network model:
In this model, there is only one hidden neuron, the input layer has three inputs, and finally one output. layer.
When we set the activation function for the hidden layer (Hidden layer), the hidden layer becomes as follows:
and proceed according to the following formula Calculation, in this formula, all activation functions are sigmoid functions by default. Here, the theta of each neuron node is theater+1, and theta0 is the bias parameter.
Here, the input x is vectorized and simplified into the following formula:
The final calculation result is:
The next chapter is to use sigmoid and neural network to do some and and or operations, as shown in the figure below:
After the above network operation, the same logical or can be made Effect.