Page 256 - DCAP310_INTRODUCTION_TO_ARTIFICIAL_INTELLIGENCE_AND_EXPERT_SYSTEMS

Introduction to Artificial Intelligence & Expert Systems

Notes It also means that adding or modifying rules to an expert system can effect changes in program
behavior without affecting the controlling component, the system shell.
The language used to express a rule is closely related to the language subject matter experts use
to describe problem solutions. When the subject matter expert composes a rule using this language,
he is, at the same time, creating a written record of problem knowledge, which can then be
shared with others. Thus, the creation of a rule kills two birds with one stone; the rule adds
functionality or changes program behavior, and records essential information about the problem
domain in a human-readable form. Knowledge captured and maintained by these systems
ensures continuity of operations even as subject matter experts (i.e., mathematicians, accountants,
physicians) retire or transfer.
Furthermore, changes to the Knowledge-base can be made easily by subject matter experts
without programmer intervention, thereby reducing the cost of software maintenance and
helping to ensure that changes are made in the way they were intended. Rules are added to the
knowledge-base by subject matter experts using text or graphical editors that are integral to the
system shell.

!

Caution Don’t apply semantics directly.

Task Draw a probabilistic logic to find factorial of any number.

Self Assessment

State whether the following statements are true or false:

16. The reliability of an expert system is the different from the reliability of a database.
17. Evolving an expert system is to add, modify or delete rules.
18. Valuable knowledge can appear with the death, resignation or retirement of an expert.

13.7 Summary

Expert systems are designed to solve complex problems by reasoning about knowledge,
like an expert, and not by following the procedure of a developer as is the case in
conventional programming.

The Knowledge-base Editor is a simple text editor, a graphical editor, or some hybrid of
these two types.

The Rule Engine (often referred to as an inference engine in AI literature) is responsible
for executing Knowledge-base rules.
A rule-based system consists of if-then rules, a bunch of facts, and an interpreter controlling
the application of the rules, given the facts.
The non-production system architecture of certain expert system does not have
rule-representation scheme.

Frames are structured sets of closely related knowledge, such as an object or concept
name, the object’s main attributes and their corresponding values, and possibly some
attached procedure (if needed, if added, if-removed procedures).

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