**Previous message:**masoud nikravesh: "BISC: Intractability Principle"**Maybe in reply to:**Stefanie Koester: "Neuro-Fuzzy with categorical input?"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

Stefanie Koester wrote:

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*> Hi!
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*>
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*> I'd like to use a neuro-fuzzy method on the classification of data.
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*> Unfortunately, the input values are both rational and nominal. Can
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*> categorical input be handeled by neuro-fuzzy classification methods,
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*> i.e. by introducing dummy variables? Where can I find some literature on
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*> this subject? I would appreciate your help very much,
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I wonder if you are thinking of a fairly classical fuzzy rule-base

system: i.e. fuzzifier, fuzzy rule-base, defuzzifier, where fuzzy

rule-base is a (possibly fuzzy) relation between fuzzy sets defined on

the input universe and fuzzy sets defined on the output universe, i.e.

source of the relation is a set of fuzzy sets and the target is another

set of fuzzy sets.

If this is the case, and the inputs are defined by at least ordinal

quantities, the source fuzzy sets are normally overlapping.

However, if one input value (say one dimension of many) is nominal, it

seems to me that the lack of order in values in that dimension may be

expressed (not expressed) by ensuring that the set of fuzzy sets on that

dimension are defined using singleton (delta function) (or

no-overlapping rectangular function) fuzzy sets. Such membership

functions may be combined (in fuzzy cartesian products) with

overlapping/graded membership functions. So long as there is no overlap

in membership functions, no order is expressed (I think?).

[However, thinking aloud, say we have, of p input dimensions, one

nominal dimension with a set of L values, then the resultant system will

decompose into Q fuzzy systems defined on the remaining p-1 inputs]. In

the past, I have written something fairly naive on this topic --

claiming to have discovered even more universality of fuzzy rule-base

systems! If you wish, I may be able to find it.

Incidentally, by rational, maybe you mean 'real'? By 'ordinal' I mean

values on which an order is defined, i.e. commonly integer or real. As

for nominal, I take that to mean 'purely label'.

Best regards,

Jon C.

-- Jonathan G Campbell, Computer Science, Queen's University Belfast, BT7 1NN Tel +44 (0)28 90 274623 jg.campbell@qub.ac.uk http://www.cs.qub.ac.uk/~J.Campbell/############################################################################ 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

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