Expert systems development utilizing heuristic methods.

86 Pages·1.2 MB·en_US

by  Lewis, John N.

NAVAL POSTGRADUATE SCHOOL
MONTEREY, CALIFORNIA
THESIS
EXPERT SYSTEMS DEVELOPMENT
UTILIZING
HEURISTIC METHODS
by
John N. Lewis
June 1996
Thesis Advisor: Hemant Bhargava
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June 1996 Master's Thesis
TITLE AND SUBTITLE: Expert Systems Development Utilizing 5. FUNDING NUMBERS
Heuristic Methods
6. AUTHOR(S) LT John N. Lewis, USNR
PERFORMINGORGANIZATION NAME(S) AND ADDRESS(ES) PERFORMING
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Monterey CA 93943-5000 REPORTNUMBER
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11. SUPPLEMENTARY NOTES The views expressed in this thesis are those ofthe author and do not reflect the
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13. ABSTRACT(maximum 200words)
This thesis analyzes the diagnostic domain and isolates the heuristics employed by experts
to arrive at diagnostic solutions. These heuristic methods are then generalized in order to arrive
at a series of heuristic rules that can be applied to a wide range of diagnostic processes
independent of there respective domain. To test the validity of the generalized heuristics, a
prototype expert system was created targeting the heuristics employed by avionics repair
technicians in repair of the APS-1 15 radar system on the P-3C Orion.
14. SUBJECTTERMS Expert System, Prototype, Knowledge Acquisition, Heuristic 15. NUMBEROF
PAGES 82
Development, Heuristic, P-3C Orion, Avionics Maintenance, Diagnostics,
Troubleshooting 16. PRICECODE
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CATION OFREPORT CATIONOFTHIS PAGE TIONOFABSTRACT ABSTRACT
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Approved for public release; distribution is unlimited.
EXPERT SYSTEMS DEVELOPMENT
UTILIZING
HEURISTIC METHODS
John N. Lewis
Lieutenant, United States Navy Reserve
B.A., California State University, Sacramento, 1984
Submitted in partial fulfillment
ofthe requirements for the degree of
MASTER OF SCIENCE IN INFORMATION TECHNOLOGY
MANAGEMENT
from the
NAVAL POSTGRADUATE SCHOOL
June 1996

DUBLEY KNOX LIBRARY
NAM&L POSTGRADUATE SCHOOL
MONTEREY CA 93943-5101
ABSTRACT
This thesis analyzes the diagnostic domain and isolates the heuristics employed
by experts to arrive at diagnostic solutions. These heuristic methods are then
generalized in order to arrive at a series ofheuristic rules that can be applied to a wide
range of diagnostic processes independent of there respective domain. To test the
validity of the generalized heuristics, a prototype expert system was created targeting
the heuristics employed by avionics repair technicians in repair of the APS-1 15 radar
system on the P-3C Orion.
VI
...
TABLE OF CONTENTS
INTRODUCTION
I. 1
BACKGROUND
A.
1
OBJECTIVES
B.
1
THE RESEARCH QUESTIONS
C. 1
SCOPE
D. 2
METHODOLOGY
E. 2
F. THESIS ORGANIZATION 3
BACKGROUND
n. 5
A. THE AVIATION MAINTENANCE SYSTEM 5
1 Levels ofmaintenance 5
a. Organizational Level Maintenance 5
b. Intermediate Level Maintenance 6
c. Depot Level Maintenance 7
d. Other Technical Support 7
2. Maintenance Scenario 8
3. The A-799 Rate 9
EXPERT SYSTEM
B. 9
DOMAIN SELECTION
C. 11
D. THE APS 115 RADAR SYSTEM 12
m. EXPERT SYSTEM SOLUTIONS 13
DIAGNOSTICS
A. 13
EXPERT SYSTEMS IMPLEMENTATIONS
B. 13
1. GTE COMPASS System 14
2. MK-92 Maintenance Advisor System 15
3. The Interactive Fault Diagnosis System 16
4. Automotive Engine Troubleshooter 17
MYCIN
5. 17
SEPARATING DIAGNOSTICS FROM THE DOMAIN
C. 18
IV. HEURISTIC DEVELOPMENT FOR DIAGNOSTIC SYSTEMS 21
A. HEURISTIC DEFINITION 21
1 Heuristic Example 21
2. Benefits OfGeneralization 22
3. Heuristic Representation 23
- > B. HEURISTIC GENERATION 23
Abduction 24
1
a. Pseudo-code Representation 25
2. Commonality 25
a. Pseudo-code Representation 26
vn
...
3. Cross Commonality 27
a. Pseudo-code Representation 27
4. Complexity 28
a. Pseudo-code Representation 28
C. PROTOTYPE KNOWLEDGE ACQUISITION 29
1 Initial Steps 30
2. The Expert 31
IMPLEMENTATION
D. 31
E. PROTOTYPE DESIGN 32
V. TEST AND VALIDATION 33
A. PROTOTYPE TESTING 33
1 Initial Prototype Improvements 33
2. Subsequent Improvements 34
3. Knowledge Acquisition Issues 35
B. HEURISTIC TESTING 35
Abduction 36
1
2. Commonality 36
3. Cross-Commonality 37
4. Complexity 37
C. FINAL TEST 38
VI. LESSONS LEARNED 39
A. KNOWLEDGE ACQUISITION 39
B. KNOWLEDGE REPRESENTATION 40
C. IMPLEMENTATION 40
D. CLIPS INTERFACE 41
CONCLUSION
E. 41
APPENDIX A. PROTOTYPE SYSTEM CODE 43
APPENDIX B. APS 115 RADAR SYTEM 65
LIST OF REFERENCES 71
INITIAL DISTRIBUTION LIST 73
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