Table Of ContentPergamon Titles of Related Interest
Titles in the Series
Cantu-Ortiz/ OPERATIONAL EXPERT SYSTEM APPLICATIONS IN MEXICO
Lee/ OPERATIONAL EXPERT SYSTEM APPLICATIONS IN THE FAR EAST
Liebowitz/ OPERATIONAL EXPERT SYSTEM APPLICATIONS IN THE UNITED STATES
Liebowitz/ PROCEEDINGS OF THE WORLD CONGRESS ON EXPERT SYSTEMS
Suen & Shinghal/ OPERATIONAL EXPERT SYSTEM APPLICATIONS IN CANADA
Zarri/ OPERATIONAL EXPERT SYSTEM APPLICATIONS IN EUROPE
Other Book Titles of Related Interest
Crespo/ REAL TIME PROGRAMMING
DeCarli/ LOW COST AUTOMATION COMPONENTS
Mladenov/ DISTRIBUTED INTELLIGENT SYSTEMS
Mowle/ EXPERIENCE WITH THE MANAGEMENT OF SOFTWARE PROJECTS
Reinich/ LARGE SCALE SYSTEMS
Rodd/ ARTIFICIAL INTELLIGENCE IN REALTIME CONTROL
Journals
ANNUAL REVIEW IN AUTOMATIC PROGRAMMING
COMPUTER LANGUAGES
COMPUTERS & ELECTRICAL ENGINEERING
COMPUTERS & GRAPHICS
COMPUTERS & MATHEMATICS WITH APPLICATIONS
COMPUTERS & OPERATIONS RESEARCH
COMPUTING SYSTEMS IN ENGINEERING
ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE
EXPERT SYSTEMS WITH APPLICATIONS
MATHEMATICAL & COMPUTER MODELLING
MECHATRONICS
MICROELECTRONICS & RELIABILITY
NEURAL NETWORKS
PATTERN RECOGNITION
Operational
Expert System
Applications
in Canada
Edited by
ChingY.Suen & Rajjan Shinghal
Center for Pattern Recognition and Machine Intelligence
Concordia University
PERGAMON PRESS
Oxford · New York · Seoul · Tokyo
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Copyright© 1991 Pergamon Press Inc.
All Rights Reserved. No part of this publicotion moy be reproduced,
stored in o retrievol system or transmitted in any form or by any means:
electronic, electrostatic, magnetic tape, mechanical, photocopying,
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Library of Congress Cataloging-in-Publication Data
Operational expert system applications in Canada / (edited) by Ching Y.
Suen and Rajjan Shinghal.
p. cm.
Includes index.
ISBN 0-08-040431-1
1. Expert systems (Computer science)--Canada. 2. Application
software-Canada. I. Suen, Shing Y. II. Shinghal, Rajjan, 1945-
QA76. 76.E95063 1991
006.3 3 0971--dc20 91-11584
CIP
Printing: 123456789 10 Year: 1234567890
Printed in the United States of America
(o5)™ The paper used in this publication meets the minimum requirements of
American National Standard for Information Services -- Permanence of
Paper for Printed Library Materials, ANSI Z39.48-1984
Preface
Expert systems are now widely used in dif tem for configuring local area networks to
ferent parts of the world for various applica satisfy some given user requirements.
tions. In the past 4 years we have witnessed The next two chapters cover applications
a steady growth in the development and de related to electric power and circuit boards.
ployment of expert systems in Canada. Re The third chapter discusses expert systems
search in this field has also gained consider that have evolved for the preliminary design
able momentum during the past few years. A of high-voltage electric power networks, while
number of papers have been presented by the fourth chapter presents a system for as
Canadians at international conferences. sisting in the manufacture of printed circuit
Many seminar series and symposia on this boards.
subject have also been organized by both in Related to health and medicine, Chapter
dustrial and academic sectors. However, the 5 describes a system for advising users on how
field of expert systems is still quite young in to reduce the risks of developing cancer.
Canada, and much more effort has yet to be The two chapters that follow are concerned
devoted to it before we can make full use of with applications in the legal field. Chapter 6
this high technology. In the course of collect discusses a system to advise a lawyer whether
ing papers for this book, we noticed great re his client has grounds to sue someone for the
luctance by several industrial groups in re tort of negligently inflicted shock. Chapter 7
vealing and describing the types of expert sys presents an expert system to check the avail
tems they have developed or are using. It was ability of a proposed corporate name based
only after an extensive effort that we gradually
on the law about the proposed name being
received a reasonable response from our col
similar to an existing name, too general, or
leagues in this community. But as is obvious,
misrepresentative of the corporation's activ
this book does not cover all the expert systems
ities.
in Canada in 1990, but rather a representative
The next two chapters are related to land
subset of them. The expert systems described
transportation and the electromechanical
here were selected from those who responded
parts of a ship that operates near the North
to our invitation, which was extended to a
Pole. Chapter 8 discusses an expert system
large number of Canadian scientists and or
related to the design of intersections where
ganizations active in expert systems and their
three or four roads meet at the same level,
applications.
with no underpasses or overpasses. Chapter
This book contains 13 chapters contrib 9 describes a system for detecting potential
uted by 31 experts from universities and in problems by analyzing the vibrations of
dustries across Canada, covering a wide range pumps, compressors, fans, turbochargers, en
of applications. These chapters are organized gines, winches, and motors on icebreakers.
as follows. Chapters 10 and 11 present expert systems
The first two chapters present expert sys that assist users in making decisions and in
tems for applications in telecommunications. terpreting data. The former describes a mul-
The first reviews expert systems that have tiexpert system to assist human resource de
been developed to provide consultations to partments in carrying out hiring tasks. The
field technicians for troubleshooting tele latter discusses a system for interpreting the
phone equipment. The second presents a sys results of statistical analyses.
VI l
νιιι Preface
Chapter 12 describes an expert system for this book; Mr. Francois Coallier, Associate
the diagnosis of automobile engine troubles. Director of the Division of Quality Engineer
The last chapter discusses fuzzy logic-based ing and Research of Bell Canada; the collab
systems for the management of operations orations of our colleague Professor Peter
such as production planning, scheduling, and Grogono and research associates Alan Bloch
inventory control. and Alun Preece; and the help offered by our
The preparation of this book was sup secretary Irene Mazis. Finally, this project
ported in part by Bell Canada through a re could not have been realized without the
search contract related to the verification and strong support of all the contributing authors
validation of expert systems, and by research who have devoted tremendous efforts to re
grants from the Natural Sciences and Engi search and development of the field of expert
neering Research Council of Canada, the systems in Canada and turning them into
Ministry of Education of Quebec, and the practical applications.
Centre for Pattern Recognition and Machine
Intelligence of Concordia University. We also Ching Y. Suen
wish to acknowledge the encouragement Rajjan Shinghal
given by Professor Jay Liebowitz of George Montreal, Canada
Washington University, the series editor of January 1991
Diagnostic and Administrative Expert Systems
at Bell Canada Network Services
R. DOUGLAS BELL
Network Maintenance, London, Ontario, Canada
OVER THE PAST 3 years, a growing family of available to others the knowledge and expe
specialized diagnostic and administrative ex rience of an expert in some specified field.
pert systems has been developed for the use Expert systems have in a few short years cre
of Bell Canada staff in Ontario, using com ated a robust niche for themselves in indus
mercially available expert system shells. While trial and commercial spheres, where the pay
the early prototype systems were confined to off for the work involved in developing them
PCs, the applications have spread in rele is frequently easy to demonstrate. For ex
vance, usage and platform; currently the same ample, the difference between a newly trained
knowledge base developed on a PC is being technician and an expert repairman is the lat-
accessed via a Province-wide network of some ter's accumulation of practical knowledge and
3000 terminals, from a VAX mainframe. The experience, which can be transferred to the
total package currently amounts to some 6 trainee either directly and face-to-face, or by
megabytes of source code, and the largest ap encoding it in a widely available interactive
plication module to date embodies over 1,300 program. As the experiences described in this
rules. Field and managerial acceptance has paper demonstrate, this second approach is
been enthusiastic; experience has indicated often more efficient and cost effective.
some unconventional coding techniques and Major corporations noted for in-house
extended usefulness. At present, diagnostic implementation of expert systems include
expert system modules offer field support to IBM (i.e., the Training Advisor program,
trained technicians in the repair of nine dif which suggests professional staff development
ferent types of hardware device; at least as directions), DEC (the famous Rl computer
many more such systems are in various stages system design consultant), Ford and General
of development. Less classical expert system Motors (on-the-floor assembly-line robot
applications include indices to the volumi maintenance, among others), E. I. du Pont
nous internal corporate documentation con (where ad hoc local expert systems have
cerning policies, procedures, personnel ben sprung up in many divisions and depart
efits forms, technical notes and safety pro ments), and the Bell family of communica
cedures. The usefulness and cost-effectiveness tions companies. Many of these endeavors
of this innovative technology has been amply have monopolized the effort of sizable profes
demonstrated to the Bell community; usage sional programming teams for several years
of the package is spreading to neighboring of development time before any rewarding
provinces. product emerges; but, as demonstrated here,
it is also feasible to implement useful systems
in a matter of a few man-days, with the aid
GENERAL BACKGROUND
of appropriate shell packages. Some modern
The term expert system is applied to a com high-tech electronic hardware items come
puter program that incorporates and makes complete with their own intrinsic chip-
1
2 Operational Expert System Applications in Canada
embedded diagnostic expert systems based on Maintenance system). That same year, field
the same shells. trials (including training of technicians and
Diagnosis, or reasoning from a known set managers) proved the benefit of the approach,
of symptoms to identify their (necessarily ex and stimulated nomination of 60 other device
isting) common root cause, is one of the most types for similar diagnostic treatment; sub
popular (as well as most readily implemented) sequent managerial prioritization targetted 15
applications of expert system technology. of these for early implementation.
Others include monitoring real-time on-line It should be pointed out that the applica
input data (such as from various sensors in tion area involves many different solid-state
an industrial process or hostile environment) devices, which characteristically work prop
and interpreting them by reference to pre erly for a long time between failures. Such
defined normal value sets, or the design, failures are always catastrophic to a greater
planning, control or optimized configuration or lesser degree, since the purpose of the entire
of a presently nonexisting complex system (a system is to maintain reliable, uninterrupted
much more demanding, and less prevalent, telephone service to Bell subscribers any
application, where in general it is difficult to where. A problem always requires urgent
guarantee the existence of a best solution). troubleshooting due to the pressure to restore
full service as rapidly as possible. Although
most technicians have been trained on most
BELL NETWORK SERVICES
equipment, many months may elapse be
PROJECT
tween their training on a particular device and
Before he had ever encountered the term ex the call to apply it; such a call could come at
pert system, the author's background in 2 a.m., demanding repairs to be made in 2 ft
minicomputer maintenance crystallized in a of snow, 2 hours' drive from civilization. The
BASIC-language program he developed in development of these expert systems is con
1985 to interpret hexadecimal error messages sequently need-driven!
for the benefit of nontechnical computer sup The current project at Bell Canada has
port staff, and advise them as to appropriate demonstrated that homegrown expert systems
follow-up steps; this application was recog are capable of presenting troubleshooting
nized a year later as a de facto expert system. consultation to a field technician as an expert
In 1988 he was one of a small group of Bell would, and drawing logical conclusions (in
staff who underwent training in the use of a cluding spotting when the user is hopelessly
commercial expert system shell package; they lost, and referring him to a support hot line);
went on to develop and distribute a prototype the interactive systems support revision of
diagnostic maintenance program for a partic user input responses, storage of the current
ular piece of frequently repaired communi status of an inquiry for later continuation (es
cations equipment, but this product never pecially useful when attempting to alleviate
gained widespread acceptance because it ran intermittent malfunctions), on-line context-
only on PCs, which were inaccessible to most sensitive help to the user, and compatibil
of the technical staff who could have used it. ity with most existing network maintenance
That developmental effort was not entirely terminals.
wasted, however, as the knowledge base was The proven benefits enjoyed as a result of
translated in 1989 into another shell environ implementing these diagnostic expert systems
ment which runs the same rule bases on PCs, include:
Macintoshes, and VAX mainframes and can 1. upgrading the performance of technicians
be queried from any VT100- or VT220-com- to expert level;
patible terminals (of which some 3,000 are in 2. reinforcing previous technical staff training;
use throughout the Bell Canada Network 3. extending technical support availability to
Diagnostic and Administrative Expert Systems 3
24 hours per day, while drastically de approach to new topics, on the part of both
creasing demands on support personnel field users and the developer: "If it can do X,
and minimizing the possible embarrass why not Y, Z, and A as well?" Programmers
ment entailed in having to ask a colleague themselves frequently come up with unor
for assistance; and thodox new ideas from trying innovative an
4. decreasing downtime of crucial systems by gles indicated by perceived need, such as in
expediting prompt repairs and mainte corporating text-heavy technical document
nance. retrieval and personnel benefit forms handling
Additional benefits uncovered in the pres into the package. After all, they are also do
ent shell approach (as opposed to de novo mains of isolated expert knowledge of great
programming) include a much faster learning potential usefulness to the Bell community
curve, as well as ease of updating the knowl at large, if only some method can be found
edge base and incorporating preexisting text, to make them more widely accessible. A
such as corporate engineering and technical seemingly unrelated application, recently de
documentation. veloped under considerable demand, is a
schematic presentation of standardized cor
porate safety procedures (starting out with
"Whom to Call in Case of an Accident"),
DEVELOPMENT PROCESS
which turns out to lend itself nicely to the
rule-based expert system approach. (See
Problem Selection
Figure 1.1.)
The technical literature in the expert systems
field is fairly consistent in recommending cri
Knowledge Acquisition Process
teria for evaluating the appropriateness of in
vesting developmental effort in expert sys In the Bell Canada environment, it is gener
tems. One looks for: ally not difficult to identify the unique expert
1. a well-defined, high-profile subject area in the maintenance ofany particular piece of
(one where frequent problems motivate equipment; in at least one prominent case,
such treatment), in which only a low level that individual was facing retirement, which
of expertise is generally available; strengthened the motivation to capture his
2. the availability of expertise for the ongoing benefit of the staff
a. a cooperative and committed subject and user community at large. During the de
matter expert, velopment of the first half-dozen diagnostic
b. a competent project developer, and systems, a stable knowledge acquisition
c. hardware and software tools adequate methodology has been refined; this process
to render the project potentially prac characteristically transpires during a series of
ticable; and direct interviews, generally limited to 2 hours
3. a high level of management support. at a stretch, each of which may give rise to
In the present case, as mentioned above, an average of 3 days of implementation work
once the pioneering module was up and run followed by some 4 hours of testing the ex
ning and demonstrated the potential useful panded prototype.
ness of the application, there was little diffi Initially the potential scope of the appli
culty in identifying subsequent target areas; cation is mapped out by applying the tradi
the challenge was more to decide which were tional "divide-and-conquer" analytical ap
most urgent. proach to the possible array of malfunction
One consistent theme characterizing the symptoms. This hierarchical analysis system
project to date is the recurring realization of atically rules out irrelevant hypotheses and
the potential for applying the expert system focuses on the essence of the problem. At the
4 Operational Expert System Applications in Canada
INTRODUCTORY MENU SCREEN
Network Maintenance Expert System
Please select a Subject Area of interest to you.
To select a subject area, type the number corresponding to the Subject below
and press the RETURN key.
Press EXPL function key for General Instruction & Hints
Te chnical Advisors Administrative Advisors
1. DMS1 10. Benefit Forms, Publications & Numbers
2. DMS1U 11. Index of TIPS & MELS
3. TUC (Touchtone Usage Controller) 12. General Circulars
A. LD-1 Line Problems 13. BSPs, BCPs, NTPs
5. ML TU 14. N. T. A. S. Directory
6. PC-ANI 15. Safety
7. DRTU Other Advisors
8. Alston 383A, 615, 616, 616 m/s 16. Expert System User Manual
9. Transmission Improvement 17. View the System Update Notices
18. Leave a Message for the Programmer
0. Exit from the System (Log Off)
3 STRT 5 EXPL 6 WHY? 8 MENU 9 HELP 10 EXIT
FIGURE 1.1. Introductory menu screen. Undocumented numeric options (such as 19 or 20) allow system
users who are aware of their existence to access incomplete modules still under development. The masks
along the bottom margin of the screen image are labels for function keys.
same time, some detailed example cases are ternative of logical testing of electronic signals
analyzed from the expert's experience. On the at all pertinent nodes of the circuitry. The
basis of the preliminary decision tree a pro principle throughout the development process
totype program is devised of limited breadth is that the expert knows the shortest way to
and depth, but sufficient to illustrate the ap arrive at and fix the problem, by experience,
proach to the domain expert; flow charts are which is predictably faster than thumbing
also frequently developed (and sometimes through technical manuals on the spot.
even provided by the expert) to utilize the In outline, then, the knowledge acquisition
common (but often overlooked) eidetic an and development process is as follows:
alytical skills of such experts. This method of 1. initial interview and scoping of the appli
presentation avoids imposing the incomplete cation;
series of computer screen displays on them 2. construction ofa demonstration prototype
and offers conceptual feedback for detailed based on a subset of the domain;
evaluation. The ultimate goal of the knowl 3. review of the prototype with experts (for
edge acquisition process is to produce a de relevance) and users (for acceptability);
cision tree that embodies most known pat 4. further knowledge acquisition interviews
terns of malfunction, and identifies the most and refinement and/or expansion of the
appropriate repair tactic for each. The final prototype system; and
tree is approximated through several itera 5. iteration of steps 3 and 4 until the proto
tions of refinement. type is deemed acceptable, after which it
What is being acquired here is heuristic becomes an operational knowledge base.
knowledge in terms of high-level rules of This procedure is essentially analogous to
thumb, which efficiently relate symptoms to the conventional rapid prototyping method,
their most likely causes rather than deep used here in expert system development in
causal-level knowledge of electronic device stead of standard software engineering.
behavior. This approach to modeling the di It should be pointed out in this context
agnostic problem has proven not only quite that highly qualified technical experts exhibit
reliable, but much more efficient in terms of a wide range of degrees of insight into, and
rapid convergence on the defective subunit ability to express verbally, their knowledge
than the more instrumentation-intensive al and problem-solving techniques; the knowl-
Diagnostic and Administrative Expert Systems 5
edge engineer must employ whatever com knowledge base into shortcut and detailed
munication strategy proves most effective in reasoning paths, presenting the faster ap
a given personal relationship, constantly proach first.
bearing in mind that his program develop
ment project is dedicated to serving the needs
Knowledge Representation
of the expert and his colleagues, and not vice
versa! The comfort and interest of the expert The shell tool in use, Level 5 from Informa
must be maintained throughout the pro tion Builders, has proven adequate for rapid
tracted early development steps, largely by prototyping of diagnostic expert systems (al
both dealing appropriately with his subjective though it might not suffice for other, more
ego needs and providing him with rapid feed demanding areas of expert system application,
back to each interview session. such as configuration, pattern recognition,
In designing the text windows selected for and qualitative modeling). It represents expert
display to the questioning user, presenting the knowledge in the common form of sets of
actual words of the expert to the client com logical production rules of the form IF A
munity has proven beneficial in enhancing AND B AND NOT C THEN D, which serve
comprehension of the concepts, content, and as grist to the built-in inference engine. (Other
direction of thought. A cultural choice must commercial shells implement frame or se
be constantly made as to whose jargon is to mantic net representations, or some hybrid
be employed, with the obvious choice being of these.) Level 5 supports Boolean logical
that of the field engineer, not the programmer. variables, whose names can be up to 60 char
Tools commonly employed to support the acters in length for readability, handles single
knowledge acquisition process include a or multiple-choice user input, performs in
standing easel or padboard, for large-scale dicated arithmetic computations, and allows
sketching of entities in the system under con access to external databases (although this
sideration and their relationships, and an feature has not yet been used in the current
electronically rotating padboard that dumps project). An earlier generation of the same
an image of the flowchart to FAX paper. The product, marketed as Insight Plus, has re
same ends can equally be met by using a plain sulted in the development of hundreds of ap
pad of paper; in this case, the expert watches plications at E. I. du Pont.
and verifies the knowledge engineer's record After achieving poor speed performance
ing of each concept, and pages are numbered (an order of magnitude too slow) from an
to maintain conceptual relationships. Nei early knowledge base coded as short rules (IF
ther audio nor video recording has been A THEN B, IF B THEN C, IF C THEN D),
used, largely to avoid intimidating senior the author established the policy of encoding
employees. an entire chain of inference in each rule; thus,
During the development of a few diagnos most rules present a visible conclusion to the
tic modules, multiple experts were involved; user, without a plethora of intermediate vari
they characteristically revealed complemen ables. The resulting rule form, IF A AND B
tary sets of partial knowledge, none of which AND C THEN GOAL AND DISPLAY
were necessarily invalid. For example, re CONCLUSION, avoids both reevaluating the
gional disparities surfaced with regard to op variables A, B, and C, and also tracing an
timal testing methodology; both were perti involved chain of inference before reaching
nent given certain scenarios, and the ultimate the conclusion; this implies that any single
resolution stemmed from responses to ques symptom may appear in a number of rules,
tions such as "Under which circumstances but the redundancy at the source-code level
might you use the other approach?" In one is rewarded with greatly improved perfor
case it proved necessary to segregate the mance. This approach to knowledge base de-
