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