Hi All,
In the 2nd point out here, Todd says that if there is a complex logic using
the rule based systems is effective.
I can't get this point. After all i can replace the loop he has give with
If (a and b) then f
If (a and not(b) and c) then g
...
...
After all in a rule based system, u are going to write rules like that only !!!!
So why can't i write them in a procedural code.
I still can't get this point.
Also if you write each rule in a rule based approach as an if loop in procedural
code why will it not work???
If i want to fire the rule dynamically, then too i can implement it, say using
propertychange listener of JavaBean architecture.
Please throw some light on this.
Thanks in advance
Rakesh
"Blanchard, Todd" <[EMAIL PROTECTED]> on 03/06/2000 04:08:34 AM
Please respond to "Blanchard, Todd" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
cc: (bcc: Rakesh Ambewadkar/LTITLPUN)
Subject: RE: JESS: Need of Rule Based Systems !!!
Its gratifying to see people starting to figure out that you can't really
implement complex business rules with just objects. I wrote a couple
workshop papers at the 95 oopsla and it seemed that there was a lot of
harumphing and nobody really quite understood.
A couple points I made:
1) Objects are intentionally myopic. In an effort to maximize cohesion
and minimize coupling, designers work to minimize cross object visibility.
This is good software design but it tends to hinder the implementation of
complex constraints with conditions that have a disperse locality of
reference. For instance, trying to constrain available services in a sales
application based on a complex combination of the customer's geographic
location and tax status.
2) Complex ladder logic is fragile. If you find yourself with 2 or more
levels of nested if statements with duplicated code:
if(a)
{
if(b) then f
else if(c) then g
else if (d) then h
}
else
{
if (c) and (d) then g
else if (d) and (b) then f
}
its totally time to go to a production rules based architecture.
3) State machines require more than 1 look-back or look-ahead to decide next
state.
I implemented a work planning system using production rules because I was
able to identify
complex opportunities to reuse work and take short cuts given certain
conditions.
These are a few of the heuristics I use to decide whats algorithm and whats
better as a kb.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
eTranslate, Inc. The Power of Language
Todd Blanchard main +1.415.970.7119
Chief Technology Architect fax +1.415.371.0008
http://www.etranslate.com/
500 Treat Street, Suite 100, San Francisco, California 94110, U.S.A.
> -----Original Message-----
> From: DATA [mailto:[EMAIL PROTECTED]]
> Sent: Friday, June 02, 2000 9:41 AM
> To: [EMAIL PROTECTED]
> Subject: Fw: JESS: Need of Rule Based Systems !!!
>
>
>
>
> Giarratano & Riley "Expert Systems Principles and Programming" has a
> gooddiscussion on the different approaches.
>
> >-----Original Message-----
> >From: Sachin <[EMAIL PROTECTED]>
> >To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> >Date: Friday, June 02, 2000 5:03 AM
> >Subject: JESS: Need of Rule Based Systems !!!
> >
> >
> >>Hi,
> >>I read all the documentation of rule based systems, but am
> sorry to say
> >that
> >>i am still not able to appreciate its importance in a
> business. Can any
> >body
> >>give me some specific example and then quote out by comparing the
> >difference
> >>between the procedural and rule based approach. After all
> what is wrong
> >with
> >>encoding business knowledge in business objects of business level
> >middletier
> >>layer. Kindly quote an business example !!!
> >>Thanks
> >>Sachin
> >>
> >>
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