Their design and operation is loosely modeled after the networks of neurons connected by synapses found in the human brain and other biological systems. One can also find neural networks referred to as artificial neural networks or artificial neural systems. In order to understand the significance of the ability of a neural network to handle data which is less than perfect, we will preview at this time a simple character-recognition application and demonstrate it later. We will develop a neural network that can classify a 7x5 rectangular matrix representation of alphabetic characters. As a typical programmer can see, conventional algorithmic solution methods would not be easy to apply to this situation.
Connections exist between selected pairs of the PEs.
These connections carry the output in the form of a real number from one element to all of the elements to which it is connected. Each connection is also assigned a numeric weight. PEs operate in discrete time steps t . The operation of a PE is best thought of as a two-stage function. The first stage calculates what is called the net input, which is the weighted sum of its input elements and the weights assigned to the corresponding input connections.