What is Artificial Neural Network (ANN)?

A computer is much faster than the human brain, but cannot make its own decision, so computer scientists are trying to mimic real biological neuron to enable computers for cognition and they term it as Artificial Neuron. And an artificial neural network is inspired by inter-connectivity between the real biological neurons.

Neuron Network is also called "Perceptron"

What is the use of Artificial Neuron Network?
What is Feed-Forward & Feed-Back (Recurrent Connection)?