A knowledge-based system (KBS) is a computer program that reasons and uses a knowledge base to solve complex problems.
In addition, the knowledge may be structured by means of a subsumption ontology, frames, conceptual graph, or logical assertions.
These more formal approaches are covered in detail in the Wikipedia article on knowledge representation and reasoning.
Other examples of knowledge-based system architectures supporting meta-level reasoning are MRS[5] and SOAR.
Frames, for example, are a way representing world knowledge using techniques that can be seen as analogous to object-oriented programming, specifically classes and subclasses, hierarchies and relations between classes, and behavior[clarification needed] of objects.
For example, procedures stored as daemons on[clarification needed] objects could fire and could replicate the chaining behavior of rules.
[11] Another advancement in the 1990s was the development of special purpose automated reasoning systems called classifiers.