Give your PC some human intelligence
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º EXPERT SYSTEMS º
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º "Give your PC some human intelligence" º
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An Expert System is computer software that can solve real
world problems requiring logic, decision making and knowledge
processing. Expert Systems can also categorize, consult, analyze,
and diagnose. These software tools are useful in areas that
formerly required a human expert. Expert Systems use deductive
reasoning to solve problems that are often unstructured, and
would be impossible to approach with conventional procedural
computer techniques.
An Expert System Shell is an Expert System minus its
knowledgebase and domain. It is an Expert System ready to be
taught the rules of knowledge in a particular field. An
Expert System Toolkit is something more: a shell plus an organized
set of software tools to assist in developing it into a full
expert system. Usually, this includes an editor for building
the IF-THEN rules that make up the rulebase, a trace facility
for testing the way the rules interact, hooks to pre-existing
databases and spreadsheets, and a sophisticated user interface
that hopefully hides all these tools from the user during
the run-time consultation.
Shareware is user supported software. It is usually
distributed free through Bulletin Boards, but can also
be purchased for a disk-copying fee. Shareware
authors hope that you will like and use their software
enough to remit the requested registration fee. (Usually
$25 to $75). In return, you become a registered user,
entitled to updates and sometimes a printed manual.
There are currently about a dozen Shareware Expert Sytem
Shells on the Boards. I've downloaded and un-archived
them all, and selected six of the best.
I'm going to give you some information and opinion on each of these
Shareware Shells: ESIE, Turbo Expert Toolkit, ImpShell, XXXPERT,
Inference, and Rulemaker.
Each shell was tested with the simple rulebase in Figure 1,
which will advise you as to whether or not your PC will run the
new OS/2 operating sytem recently released by IBM for its line
of PS/2 Personal Computers. The minimum requirements for running
OS/2 are a 286 or 386 CPU and 1.5 Meg of Memory (2 Meg for OS/2
with the DOS Compatability Box). The rulebase was first developed
and tested in Level5, a popular commercial expert system shell, and then
modified in syntax as required. I'll comment on just how difficult
it was to adapt the rulebase to each shell, the ease of running the
consultation thru the provided user interface, and finally if
each inference engine generated the correct conclusion.
=============================================================================
TITLE Will Your PC Run OS/2
1. Your PC will run OS/2
2. Your PC should run OS/2 with more memory
3. Your PC will never run OS/2
RULE for Will Run OS/2
IF Your CPU is a 386
AND Your PC has 2 Meg of Memory
THEN Your PC will run OS/2
RULE for Should Run with Modification
IF Your CPU is a 286
AND Your PC has under 1.5 Meg of Memory
THEN Your PC should run OS/2 with more memory
RULE for Will Never Run
IF Your CPU is a 8086 or 8088
AND Your PC has under 1 Meg of Memory
THEN Your PC will never run OS/2
Figure 1. Original OS/2 rulebase in LEVEL/5 syntax
============================================================================
1. ESIE (Lightwave Consultants, PO Box 290539, Tampa, FL 33617 $75)
ESIE is the acronym for Expert System Inference Engine, and
that is exactly what it is. ESIE loads in a knowledge base,
and builds inferences out of the IF-THEN rules, to
act like an Advisor. It is an Artificial Intelligence expert
system shell. An infinite multitude of knowledge bases can
be used by ESIE.
The normal gamut of expert systems (ES) can be built for and
used by ESIE. Tools such as system configurators, medical
experts, oil and gas exploration, etc, can all be done in
ESIE. ESIE is a rule-based backward chaining inference
engine.
The acronym was also selected because ESIE is easy to use.
You just type ESIE at the prompt, and a one-screen shareware
ad appears. You then type the name of the rulebase to load:
DOCTOR, ANIMAL, or GLASS. ESIE then begins to ask you
questions from the rulebase. You can only respond YES or
NO. The consultation will either lead to a conclusion
or the statement "UNKNOWN". Options are TRACE ON, TRACE OFF,
GO, or EXIT. When you EXIT, Esie always says "Have a nice
day". This is an excellent shell with excellent documentation.
The full page shareware notice on the first screen is
a problem for business use, as is the "Have a nice day".
The main problem is the lack of confidence factors. You
can only answer 100% YES or 100% NO.
For ESIE, my OS2 rule base had to be restated (Figure 2).
============================================================================
goal is type.computer
legalanswers are yes no *
if cpu is no
then type.cpu is old
if cpu is yes
then type.cpu is new
question cpu is "Does your PC have a 286 or 386 CPU chip?"
if type.cpu is old
then type.computer is "your PC will never run OS/2!"
if type.cpu is new
and memory is yes
then type.computer is "your PC will run OS/2 perfectly!"
if type.cpu is new
and memory is no
then type.computer is "your PC should run OS/2 with more memory"
question MEMORY is "Does your PC have 2 meg or more memory?"
answer is "In my expert opinion " type.computer
Figure 2. Rulebase as modified for ESIE
=========================================================================
Once this was accomplished, ESIE did a perfect
job of running the consultation, and could respond
with the three possible answers appropriately.
When I turned TRACE ON, ESIE said that the rule
base had 12 rules(!), three legal questions,
and two legal answers(!). I've been informed
that this has been corrected in the latest
release of this excellent product.
2. TURBO EXPERT TOOLKIT (Thinking Software, 46-16 65th Place,
Woodside, N.Y. 11377 $59.95)
The Turbo Expert System Toolkit is based on confidence
factors (10 means yes, 0 means no, 5 means maybe, 9 means
almost definitely, etc.) In addition, with this Toolkit
you are relieved of the difficult assignment of creating
an IF-THEN rulebase in a separate ASCII text editor.
The Turbo Expert Toolkit presents the absolutely
most direct menu driven approach to generating your own
rule-based backward chaining expert system. When it is
complete, your expert system will ask you (or the user of
your system) a series of questions (QUERIES) to be answered
on a scale of 0(No) to 10(Yes). At the conclusion of the
consultation the Expert will draw a graph of the User's
responses, and finally display the correct solution (GOAL).
Turbo Expert never says UNKNOWN.
Large scale expert systems with hundreds of queries
and goals can be built, since the Knowledgebase is stored on
its own separate disk. In addition, you can build many
expert systems: just use a separate disk to store the
Knowledgebase for each. Turbo Expert comes with extensive
documentation, an online tutorial and demo, plus a Quick
Reference Chart to help you put up your first Expert System
in under one hour.
The registered version also includes two complete
Expert Systems ready to consult (The Psychology Expert &
The Stock Market Expert).
Turbo Expert leads you step by step through the process
of creating a rulebase. First I pressed 'A' on the
Main Menu, and was prompted to enter TITLE, AUTHOR and
DESCRIPTION of my rulebase. Then I pressed 1 and entered
these three queries:
1. Does your PC have an 8088 CPU and 640K of memory?
2. Does your PC have a 286 or 386 CPU and less than 2 Meg of memory?
3. Does your PC have a 286 or 386 CPU and 2 Meg or more of memory?
Next, I pressed 5 on the Main Menu and entered these
three goals, with numeric links to the appropriate queries.
1. Your PC is most similiar to the original IBM/PC and will not
run OS/2. (link with 99 to query 1)
2. Your PC will run OS/2 if you install a total of two Megs of
memory. (link with 99 to query 2)
3. Your PC was designed to run OS/2! (link with 99 to query 3).
Building the Turbo Expert Rulebase took all of 10
minutes, and the resulting consultation was the
only one with a completely natural use of english
language for the entire process.
In addition, Turbo Expert is the only one of the
Shareware Shells which comes with an independent
run-time module to insulate the user from
the development process and protect the completed
expert system.
3. IMPSHELL (Daniel H. Marcellus, Middletown Programming Works,
Middletown, New York. Public Domain)
The IMP Shell is a powerful expert system development environment for the
IBM-PC. It contains all the utilities needed to develop and test new expert
systems, and run them when they are finalized. All functions are menu
driven and appear in windows. IMP expert systems are rule based, backwards
chaining systems. They are very fast and not limited by an artificially
small number of rules.
The IMP Shell is in the public domain and is used in many educational
settings. It was developed by Daniel H. Marcellus of the Middletown
Programming Works, Middletown, New York. It is completely described in the
book "Expert Systems Programming in Turbo Prolog" which is written by
Mr. Marcellus, and published by Prentice-Hall, Englewood Cliffs, N.J. (1987).
An expert system is a program which has captured the expertise of an expert
in some field and can deploy that expertise with seemingly intelligent
behavior. For instance there are expert systems to do all these things:
Diagnose medical problems
Guide the repair of complex equipment
Give advice about taxes and investments
Guide chemists in synthesizing desired chemicals
Interpret telemetry data from satellites
Control nuclear reactors and electric utility grids
A shell makes it easy to set up an expert system by concentrating on the
problem at hand rather than on the details of a particular machine
reasoning system or artificial intelligence language. This shell was
written entirely in TURBO PROLOG, and the source code is provided,
although you don't need to understand anything about TURBO PROLOG in order to
set up an expert system with this software.
The IMP Shell is menu driven, and the menu allows you to select all the
activities that are necessary at various stages of the development
of an expert system, for example:
1. HELP information
2. MAKE rules for a new expert system
3. INSPECT the rule set that is loaded
4. SAVE the rule set that is loaded
5. LOAD an existing rule set
6. RUN the presently loaded rule set
7. EDIT an existing rule set
8. PRINT an existing rule set
9. DOS access
10. END this program
The IMP Shell uses backward reasoning. This means that it has the proper
architecture for creating good expert systems for classification
tasks, for troubleshooting, and, in general, for anything that involves
choosing among alternatives. It is not the proper architecture for
applications that require a well defined sequence of steps with
complex reasoning going into the application of each step. Applications
such as configuring complex equipment or estimating costs of a project are
of this sort. They should be implemented with a forward chaining shell.
I found Impshell more complex than the other Shells presented
here. The rulebase was difficult to create, and the consultation
insisted on displaying all the possible conclusions. The
correct conclusion had a probability of 1, while the other
two were presented in exactly the same way but with a
probability of 0. Most users would find this confusing.
============================================================================
imp("s","n","Your PC was designed to run OS/2","pos",
"the CPU is a 286/386 and the Memory is 2 meg","dummy","dummy",1)
imp("s","n","Your PC can run OS/2 after a memory upgrade",
"pos","the CPU is a 286/386 and memory is under 1.5 meg","dummy","dummy",1)
imp("s","n","Your PC will never run OS/2","pos",
"the CPU is 8088 and memory is 640k","dummy","dummy",1)
terminal_node("the CPU is a 286/386 and the Memory is 2 meg")
terminal_node("the CPU is a 286/386 and memory is under 1.5 meg")
terminal_node("the CPU is 8088 and memory is 640k")
hypothesis_node("Your PC will never run OS/2")
hypothesis_node("Your PC will run OS/2 after a memory upgrade")
hypothesis_node("Your PC was designed to run OS/2")
Figure 3. Prolog rule set required for IMPSHELL was more complex then others.
=============================================================================
4. XXXPERT (Stephen Thurber, 1926 Labrador Lane, Vienna, VA 22180 $50)
XXXPERT is an expert system development facility which
includes an editor, file manager and expert systems
inference engine packaged together in one integrated
environment.
You can use XXXPERT to develop expert systems that use rules
you write in an English language syntax. You can develop
expert systems that will aid you and others in doing things
that you would not be able to do consistently as well
without XXXPERT. XXXPERT allows you to define expert
knowledge just once then apply it repeatedly time after
time.
XXXPERT is a rule-driven system. Rules are simply
statements of logic that you wish to have applied to the
area of expertise your rules are to address. These
statements are written in English and abbreviations.
The first rule statement in a rules file must be
on a line by itself (and on the first line of the file).
This statement must specify the name of the goal for the
consultations to be performed with the set of accompanying
rules.
XXXPERT will need certain information from the user in the
course of any given consultation session depending on the
rules being used in that session. The "asks" define how
XXXPERT should ask the user (consultee) for such
information. In general you should code an ask for each
identifier that appears in the left-hand-side of a rule
(before the THEN) unless it also appears in the right-hand-
side of another rule. XXXPERT may take a little longer to
develop an Expert System, as you must develop the rulebase
first and then the Questions to ask the user, but it is
a very complete and professional product. The big problem
is the difficulty of making your consultation use
ordinary English Language.
Figure 4 and 5 shows how I had to abbreviate the
rulebase and related ASKS for XXXPERT. The consultation
had an unnatural/inhuman quality, especially the statement
of the conclusion.
=====================================================================
RUN.OS2
IF CPU EQ NO THEN RUN.OS2 EQ NEVER
IF CPU EQ YES THEN CHECKMEM
IF CHECKMEM EQ YES THEN RUN.OS2 EQ YES
IF CHECKMEM EQ NO THEN RUN.OS2 EQ WITH.MORE.MEMORY
Figure 4. The uncomfortably abbreviated rulebase required.
=====================================================================
CPU
Does your PC have a 286 or 386 CPU chip?
CHECKMEM
Does your PC have 2 meg or more memory?
Figure 5. The related ASKS could use normal English Language.
====================================================================
5. INFERENCE (George Hageman, PO BOX 11234, Boulder Colorado 80302 PD)
This inference engine is backwards-chaining only and features the
running of binary files if:
1) they are antecedents associated with a particuar consequent
being proved, or
2) they are consequents which have been proven true by verify().
their actual predicate value will be determined by their returned
result after running.
This inference engine is designed with diagnostics in mind and so
will probably be best suited for this application. Later revisons
will include forward-chaining so that the user will have the
opportunity to give pre-existant conditons, or that these may be
supplied by the calling process.
See structure design for details of operation, but basically the
inference reads in all of the compiled information as produced by the
rule compiler.
It proceeds to attempt to prove each consequent by proving the truth
or falseness of any antecedent associated with this consequent.
if any antecedent of a consequent turns out to be a consequent itself, then
the inference engine will recursively attempt to prove this
consequent. The process is complete when all of the predicate values
of the consequents has been determined.
This Shell is seriously lacking in documentation, however complete C
Source code is supplied.
The consultation could probably be more natural
(although all upper-case) with a little refinement of the rulebase.
=============================================================================
! THIS IS THE KNOWLEDGE BASE FOR THE
! OS/2 EXPERT SYSTEM FOR INFERENCE
!
IF PC HAS 8088-CPU
ANDIF PC HAS MEMORY OF 640K
THEN PC IS OLDPC
!
IFNOT PC IS OLDPC
ANDIF PC HAS MEMORY LESS THAN 1.5 MEG
THENHYP PC IS WILL-RUN-OS/2-WITH-MEMORY-EXPANSION
!
IFNOT PC IS OLDPC
ANDIF PC HAS MEMORY 2 MEG OR MORE
THENHYP PC IS WILL-RUN-OS/2-PERFECTLY
!
IF PC IS OLDPC
THENHYP PC IS WILL-NEVER-RUN-OS/2
!
IFNOT PC IS WILL-NEVER-RUN-OS/2
IFNOT PC IS WILL-RUN-OS/2-WITH-MEMORY-EXPANSION
IFNOT PC IS WILL-RUN-OS/2-PERFECTLY
THENHYP THIS PC IS NOT WITHIN MY KNOWLEDGE
Figure 6. Rulebase for Inference must be compiled before running
=============================================================================
6. RULEMAKER (Samuel H. Smith, no address given, Public Domain)
This unique program allows you to painlessly prepare a set of
rules for a decision-tree based expert system. It can be fun!
You teach the expert by repeatedly "Learning" new facts.
When you have your rules working properly, you can generate
a stand-alone expert system in Turbo Pascal.
MENU SELECTIONS:
New Create a new knowledge base
Read Read a knowledge base from disk
Write Write the current knowledgebase to a file
Display Display the rules in the current knowledgebase
Program Generate a Turbo Pascal Source Program
Learn Run this knowledgebase and learn new rules
Quit Exit to DOS
Two complete knowledgebase files are included:
MECHANIC....diagnose your car
LANGEXP.....Choose the appropriate computer language
for your next programming project.
This clever little system was a pleasure to work with.
The rulebase is generated interactively in "Learn"
Mode. A very nice feature is that you can always
go back to your original rulebase and teach it
more rules. When you are happy with it, you can
generate a Turbo Pascal Source Program, ready to
be compiled into a stand alone Expert System.
==============================================================================
OS/2 EXPERT SYSTEM
Q:Does your PC have an 8088 CPU and 640K of memory?
YC:Your PC will never run OS/2
NQ:Does your PC have a 286 or 386 CPU and less than 1.5 Meg Memory?
YC:Your PC will run OS/2 with a Memory Upgrade
NQ:Does your PC have a 286 or 386 CPU and over 2 Meg of Memory?
YC:Your PC will run OS/2 perfectly!
NC:No conclusion
Figure 7. This compact rulebase was generated by RULEMAKER
=============================================================================
{Expert program OS2.PAS generated by Rulmaker}
{$I PXG.INC}
begin
repeat
writeln;
writeln('OS/2 EXPERT SYSTEM');
writeln;
if ask('Does your PC have an 8088 CPU and 640K of memory?') = true then
conclude('Your PC will never run OS/2')
else {Does your PC have an 8088 CPU and 640K of memory? = false}
if ask('Does your PC have a 286 or 386 CPU and less than 1.5 Meg Memory?') = true then
conclude('Your PC will run OS/2 with a Memory Upgrade')
else {Does your PC have a 286 or 386 CPU and less than 1.5 Meg Memory? = false}
if ask('Does your PC have a 286 or 386 CPU and over 2 Meg of Memory?') = true then
conclude('Your PC will run OS/2 perfectly!')
else {Does your PC have a 286 or 386 CPU and over 2 Meg of Memory? = false}
conclude('No conclusion')
until ask('Run again?') = false;
end.
Figure 8. Rulmaker also generated this Turbo Pascal Program ready to compile.
==============================================================================
All these Expert System Shells, with demo rulebases and
extensive Manuals-on-disk are available on many Bulletin Boards
for the cost of a download or from the original authors.
The original authors deserve our support, and if you like
and use their system you should remit the registration fee.
If you can't find the programs or don't have a modem or the time
to download, from Thinking Software, Inc. 46-16 Sixty-fifth Place,
Woodside, New York 11377. All six are available for $59.95 with an
informative catalog with many other AI programs and a
free demo disk. Ask for the "Expert System Pack".
*Note: as the AITUTOR was "going to press", we received permission
to include IBIS, a new and extremely powerful Expert System Shell
in our Expert System Pack. IBIS is from Intelligence Manuafacturing
Company, and is an Educational, yet fully functional version, of their
$450 Professional Version.
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