Feedforward Neural Network

What is a Feedforward Neural Network? Feedforward Neural Network Explained

A feedforward neural network, also known as a multilayer perceptron (MLP), is a type of artificial neural network where information flows in one direction, from the input layer through one or more hidden layers to the output layer. It is one of the foundational architectures used in deep learning.

The key components of a feedforward neural network are as follows:

Input Layer: The input layer is responsible for receiving the initial data or features. Each node in the input layer represents a feature or input variable. The number of nodes in the input layer corresponds to the number of input features.

Hidden Layers: Hidden layers are intermediary layers between the input and output layers. They perform computations on the input data through a series of weighted connections and activation functions. Each hidden layer consists of multiple nodes (also known as neurons), and the number of hidden layers and nodes per layer can vary depending on the complexity of the problem.

Weights and Bias: Each connection between nodes in different layers is associated with a weight. These weights determine the strength and importance of the connections. Additionally, each node in a layer (except the input layer) is typically associated with a bias term, which allows the network to adjust the output based on certain thresholds.

Activation Functions: Activation functions introduce non-linearity to the network, allowing it to model complex relationships in the data. Common activation functions used in feedforward neural networks include sigmoid, tanh, ReLU (Rectified Linear Unit), and softmax (for multi-class classification in the output layer).

Output Layer: The output layer produces the final output or prediction of the network. The number of nodes in the output layer depends on the type of problem being solved. For example, in binary classification, there would be one node representing the probability of the positive class, while in multi-class classification, each node corresponds to a different class label.

Forward Propagation: In the feedforward process, information flows from the input layer to the output layer through the hidden layers. At each node, the weighted sum of inputs is computed, and the activation function is applied to produce the output of that node. This process is repeated layer by layer until the final output is obtained.

Training and Backpropagation: The network is trained using a supervised learning approach with a labeled training dataset. The process involves minimizing a loss function that measures the difference between the predicted output and the true output. Backpropagation, an algorithm for computing gradients, is used to update the weights and biases of the network. This process iteratively adjusts the parameters to minimize the loss and improve the model’s performance.

Feedforward neural networks are effective for a wide range of tasks, including regression, classification, and pattern recognition. However, they are limited in their ability to capture complex dependencies in sequential or spatial data. More advanced architectures, such as recurrent neural networks (RNNs) and convolutional neural networks (CNNs), have been developed to address these limitations.