Expert Ssystems are computer applications which embody some non-algorithmic expertise Expert for system solving
Components certain types And Human of problems Interfaces. For Expert systems have a number of major system components and interface with individuals who interact with the system in various roles. These are illustrated below.
The individual components and their roles are explained in next slides.
■ Components and Interfaces
‡ Knowledge base : A declarative representation of the expertise; often in IF THEN rules ;
Working storage : The data which is specific to a problem being solved;
Inference engine : The code at the core of the system which derives recommendations from the knowledge base and problem-specific data in working storage;
User interface : The code that controls the dialog between the user and the system.
Roles of Individuals who interact with the system
Domain expert : The individuals who currently are experts in solving the problems; here the system is intended to solve;
Knowledge engineer : The individual who encodes the expert's knowledge in a declarative form that can be used by the expert system;
User : The individual who will be consulting with the system to get advice which would have been provided by the expert.
■ Expert System Shells
Many expert systems are built with products called expert system shells. A shell is a piece of software which contains the user interface, a format for declarative knowledge in the knowledge base, and an inference engine. The knowledge and system engineers uses these shells in making expert systems.
Knowledge engineer : uses the shell to build a system for a particular problem domain.
System engineer : builds the user interface, designs the declarative format of the knowledge base, and implements the inference engine.
Depending on the size of the system, the knowledge engineer and the system engineer might be the same person.