Contents

- 1 Why do neural networks normalize the input vector?
- 2 How to input the image to the neural network?
- 3 Why is the curse of dimensionality for neural networks?
- 4 How is batch normalization used in deep learning?
- 5 How is a column normalized in a dataset?
- 6 Is the neural network always produces same / similar outputs?
- 7 What is the floor value of a neural network?

## Why do neural networks normalize the input vector?

The reason lies in the fact that, in the case of linear activation functions, a change of scale of the input vector can be undone by choosing appropriate values of the vector . If the training algorithm of the network is sufficiently efficient, it should theoretically find the optimal weights without the need for data normalization.

## How to input the image to the neural network?

By first extracting features (e.g., edges) from the image and then using the network on those features, you could perhaps increase the speed of learning and also make the detection more robust. What you do in that case is incorporating prior knowledge.

**How to encode date as input in neural network?**

For every instance you actually care about (events in the future, the past already happened) the time variable will take on a value that is greater than any value the time variable will take in your training data. Such a variable is very unlikely to help.

### Why is the curse of dimensionality for neural networks?

This is because the computational cost for backpropagation, in particular, non-linear activation functions, increases rapidly even for small increases of . This leads to a problem that we call the curse of dimensionality for neural networks.

### How is batch normalization used in deep learning?

Batch Normalization Another technique widely used in deep learning is batch normalization. Instead of normalizing only once before applying the neural network, the output of each level is normalized and used as input of the next level. This speeds up the convergence of the training process.

**Why do we have to normalize the input for an algorithm?**

There are 2 Reasons why we have to Normalize Input Features before Feeding them to Neural Network: Reason 1: If a Feature in the Dataset is big in scale compared to others then this big scaled feature becomes dominating and as a result of that, Predictions of the Neural Network will not be Accurate.

## How is a column normalized in a dataset?

Normalizing a vector (for example, a column in a dataset) consists of dividing data from the vector norm. Typically we use it to obtain the Euclidean distance of the vector equal to a certain predetermined value, through the transformation below, called min-max normalization:

## Is the neural network always produces same / similar outputs?

EDIT: Two layers, an input layer of 2 inputs to 8 outputs, and an output layer of 8 inputs to 1 output, produces much the same results: 0.5+/-0.2 (or so) for each training case. I’m also playing around with pyBrain, seeing if any network structure there will work. Edit 2: I am using a learning rate of 0.1. Sorry for forgetting about that.

**How to normalize data before training a neural network?**

All the variables have roughly normal distributions. I consider different options to scale the data before training. One option is to scale the input (independent) and output (dependent) variables to [0, 1] by computing cumulative distribution function using the mean and standard deviation values of each variable, independently.

### What is the floor value of a neural network?

I had a simple neural network that was outputting the same value regardless of the input. During training, it was behaving normally, with training and validation loss diminishing to a floor value. The data range was in [-1000, +1000].