Page 242 - DCAP310_INTRODUCTION_TO_ARTIFICIAL_INTELLIGENCE_AND_EXPERT_SYSTEMS

Introduction to Artificial Intelligence & Expert Systems

Notes Knowledge-Acquisition Interface

The knowledge-acquisition interface controls how the expert and knowledge engineer interact
with the program to incorporate knowledge into the knowledge base. It includes features to
assist experts in expressing their knowledge in a form suitable for reasoning by the computer.
This process of expressing knowledge in the knowledge base is called knowledge acquisition.

Notes Knowledge acquisition turns out to be quite difficult in many cases – so difficult
that some authors refer to the knowledge acquisition bottleneck to indicate that it is this
aspect of expert system development which often requires the most time and effort.

Debugging faulty knowledge bases is facilitated by traces (lists of rules in the order they were
fired), probes (commands to find and edit specific rules, facts, and so on), and bookkeeping
functions and indexes (which keep track of various features of the knowledge base such as
variables and rules).

Notes Some rule-based expert system shells for personal computers monitor data entry,
checking the syntactic validity of rules.

Expert systems are typically validated by testing their predictions for several cases against those
of human experts. Case facilities – permitting a file of such cases to be stored and automatically
evaluated after the program is revised – can greatly speed the validation process. Many features
that are useful for the user interface, such as on-screen help and explanations, are also of benefit
to the developer of expert systems and are also part of knowledge-acquisition interfaces. Expert
systems in the literature demonstrate a wide range of modes of knowledge acquisition (Buchanan,
1985). Expert system shells on microcomputers typically require the user to either enter rules
explicitly or enter several examples of cases with appropriate conclusions, from which the
program will infer a rule.
User Interface

The user interface is the part of the program that interacts with the user. It prompts the user for
information required to solve a problem, displays conclusions, and explains its reasoning.
Features of the user interface often include:

Doesn’t ask “dumb” questions
Explains its reasoning on request
Provides documentation and references
Defines technical terms
Permits sensitivity analyses, simulations, and what-if analyses
Detailed report of recommendations
Justifies recommendations

Online help
Graphical displays of information
Trace or step through reasoning

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