In artificial intelligence, an expert system is a computer system that emulates the decision-making ability of a human expert. Expert systems are designed to solve complex problems by reasoning about knowledge, represented primarily as if–then rules rather than through conventional procedural code.
An expert system is an example of a knowledge-based system. Expert systems were the first commercial systems to use a knowledge-based architecture. A knowledge-based system is essentially composed of two sub-systems: the knowledge base and the inference engine. (https://en.wikipedia.org/wiki/Expert_system)
The ideal representation for a knowledge-base is an object model (often called an ontology in AI literature) with classes, subclasses, and instances. (Cf. https://en.wikipedia.org/wiki/Knowledge_base)
