# NASA Technical Reports Server (NTRS) 19890000834: Heat exchanger expert system logic

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NASA Technical Reports Server (NTRS) 19890000834: Heat exchanger expert system logic**

The reduction is described of the operation and fault diagnostics of a Deep Space Network heat exchanger to a rule base by the application of propositional calculus to a set of logic statements. The value of this approach lies in the ease of converting the logic and subsequently implementing it on a computer as an expert system. The rule base was w

Autor: **NASA Technical Reports Server (NTRS)**

Fuente: https://archive.org/

## Introducción

N89-10205
TDA Progr_s Report 42-94
April-June 1988
lq-
Heat Exchanger
Expert
System
Logic
R.

Cormier
Radio
Frequency
and Microwave
Subsystems
Section
This article describes the reduction
of the operation and fault diagnostics of a DSN
heat exchanger to a rule base by the application of propositional
calculus to a set of logic
statements.
The value of this approach lies in the ease of converting the logic and subsequently implementing
it on a computer as an -expert system.

-The rule base was written
in Process Intelligent
Control (PICON) software.
I.

Introduction
The application
calculus has great
The controls
of formal systems analysis and propositional
value in the design of an -expert system-
rule base, where the need is to model knowledge.

Propositional
calculus is a formal logic system from which conclusions are
deduced independent
of the structure of the propositions.
The
conclusions
follow uniquely from the truth or falsity of the
propositions.
Once a knowledge base has been converted
to
propositions,
assuming it has been done correctly, the process
of deduction
cannot lead to contradictions
or to invalid conclusions.

One of the consequences
is that, given an appropriate
model, every deduction is a tautology.

A description of formal
systems and propositional
calculus can be found in [I].

The
breadboard
heat exchanger expert system is described in [2].
The task described
in this article involved
the conversion
were first described
in terms of
factor.
Two
fans
are
provided,
but
these
are
only
partially
redundant.
Under certain conditions,
both fans are required.
In addition, a number of other failures can be tolerated provided the heat exchanger
is operated
locally.

The Pumps
Alternating
command can be bypassed with a local switch, in
which case both pumps may be operated simultaneously.
All
of these conditions
were described and incorporated
in the
rule base, as the expert system needed the capability to distinguish between and not...