Re: Adding more evidence


Subject: Re: Adding more evidence
From: Luis Arguelles (CARBONAR) (arguelles.cbnr@infolid.es)
Date: Thu Jan 20 2000 - 10:14:08 MET


Kami ROUSSEAU wrote:
>>>
For my M.Sc. in computer science, my subject is the development of an
expert system. I wanted to use fuzzy logic, but my director said that fuzzy
rules do not take added evidence into account. Here is the exemple that he
gave me:
(assume that the AND operator is defined as "maximum")
IF outsideIsGreen AND insideIsRed THEN objectIsWatermelon

Suppose we only have 1 fact:
a certain fruit's outside is 60% green.
we can conclude that the fruit is a watermelon with possibility 60%

Suppose we add the following evidence:
the fruit's inside is red at 40%.
after recomputing the truth value of the rule, we still get 60%.

My director says that the possibility should have increased, but it did
not,
so fuzzy logic is not appropriate for this kind of reasoning.

What do you think of his argument?"
>>>

I think your MSc director doesn't like or know FL theories. I have two
remarks to your question:

#1.
>>>
we can conclude that the fruit is a watermelon with possibility 60%
>>>
This is not very well expressed. It would be better to say: ... the fruit
has a membership value of 0.6. The diference is subtil but very important.

#2.
Usually, "maximum" is used for representing OR, so if you reformule your
rule:
IF outsideIsGreen OR insideIsRed THEN objectIsWatermelon

Then you'll see you little puzzle matches.
I would also suggest your director some FL books.

Sincerely,
Luis Arguelles
R+D Department Director
Carbonar S.A. - Spain
arguelles.cbnr@infolid.es

############################################################################
This message was posted through the fuzzy mailing list.
(1) To subscribe to this mailing list, send a message body of
"SUB FUZZY-MAIL myFirstName mySurname" to listproc@dbai.tuwien.ac.at
(2) To unsubscribe from this mailing list, send a message body of
"UNSUB FUZZY-MAIL" or "UNSUB FUZZY-MAIL yoursubscription@email.address.com"
to listproc@dbai.tuwien.ac.at
(3) To reach the human who maintains the list, send mail to
fuzzy-owner@dbai.tuwien.ac.at
(4) WWW access and other information on Fuzzy Sets and Logic see
http://www.dbai.tuwien.ac.at/ftp/mlowner/fuzzy-mail.info
(5) WWW archive: http://www.dbai.tuwien.ac.at/marchives/fuzzy-mail/index.html



This archive was generated by hypermail 2b25 : Thu Apr 06 2000 - 15:59:39 MET DST