Figure 1.

Hierarchy and interaction between main AI-based applications and methods. As explained before, expert systems are examples of hand-designed programs. Moving into the future, machine learning applications that enable machines to learn by themselves without minimum intervention have become more common in use. Deep learning, a subset of machine learning, uses artificial neural networks (ANNs) resembling the connections of neurons in the human brain to process the input in multiple layers and extract progressively higher features from it. It implements a higher learning function in AI-based systems. Created with BioRender.com.