In Scott Wallace's article ``Experts in the Field'' (October 1994), he states, ``Given that TestBench [a model-based expert system] focuses on failures and their causes, model-based reasoning tends to have limited applicability for most prospective users.'' This could not be further from the truth.
Model-based systems are much more applicable in the field of maintenance, because it is much easier to design a test to determine how a system is functioning correctly than to design one for how it might fail. A correctly designed model-based system can detect problems that have never occurred, where a rule-based system cannot; the rule to take you down that branch of the diagnostic tree would not yet exist.
Leonard J. Sparks
Silverthorne, CO
Flexible C++
Matthew Wilson
My approach to software engineering is far more pragmatic than it
is
theoretical--and no language better exemplifies this than C++.
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Why Systems Fail
