Engineer
Maintenance and
Operating Handbook
Knowledge
Acquisition
Module
Service logbook
Equipment &
Specification
Knowledge Base
Expert System Shell
User Interface
User
Inference Engine
Rules
Regulation
Method
Rule Based
• If... Then...
• backward Chaining
Figure 2: The designed framework for expert system shell
Collapsing - Collapsing the goal is the
process whereby the backward chainer
tries to determine if the goal has been
satisfied. The goal may have been satisfied
by the recent addition of new facts caused
by the Expansion process.
● ●
Asking - The third phase of the backward
chainer is where the backward chainer
queries the user for the value of a slot once
it has determined it cannot find that value
on its own.
Figure 2 shows a framework design for fault
diagnosis of a commercial bus design and
manufacturing process.
● ●
Application
Human experts are able to perform at a high level
because they know their areas of expertise.
An expert system, as these programmes are
often called, uses domain specific knowledge
to provide "expert quality" performance in a
problem domain. Generally, exper t system
developers acquire this knowledge with the
help of human domain exper ts, and the
system will emulate their methodology and
performance. An expert system is a system
with both theoretical and practical knowledge
focusing on a narrow set of problems. However,
an expert system is not human and thus is unable
to learn from its own experience. Knowledge in an
expert system must be extracted from humans
and encoded in a formal language. This is the
major task faced by designers of knowledge-
intensive problem solvers (Negnevitsky, 2005).
Expert systems neither copy the structure of the
human mind, nor are they mechanisms for general
intelligence. They are practical programmes that
use heuristic strategies developed by humans
to solve specific classes of problems. Because of
the heuristic, knowledge-intensive nature of expert-
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