Re: coupling neural networks and fuzzy logic for forecasting purposes

From: Greg Heath (heathg@miles.ll.mit.edu)
Date: Wed Dec 05 2001 - 12:26:23 MET

  • Next message: P. Sarma: "Re: Stupid question"

    Date: Wed, 28 NOV 2001 10:01:27 +0100
    From: Giorgio Corani <corani@elet.polimi.it>

    On Wed, 28 Nov 2001, Giorgio Corani wrote:

    > Harris Georgiou wrote:
    >
    > > "Giorgio Corani" <corani@elet.polimi.it> wrote in message
    > > news:3C0360CD.10004@elet.polimi.it...
    > >
    > >>...........
    > >>Roughly speaking: an identical rainfall event causes a small water
    > >>level increase if the soil is dry, and a very larger increase is the
    > >>soil is wet and does not infiltrate water.
    > >>
    > >>The problem i would to address is that my knowledge about the state of
    > >>the system is quite fuzzy (i can say for example the basin is more or
    > >>less wet)...................
    > >>
    > >
    > > Why not use the dryness of the soil as an independent input itself? Even if
    > > the estimation is subjective, you can use a scale from 1 to 10 (or whatever)
    > > and include this estimation in the input vector. If that estimation is
    > > fairly good, the training process will determine if and how much it affects
    > > the output of the system. Just a thought.
    >
    > I already thought about that. In my opinion it could not be really
    > useful: although it is possible to select a "class of dryness" for the
    > state of the soil, it will represents actually the state of the system,
    > not an input to it.
    > Since identical rainfall (i.e. identical inputs) results in a very
    > different runoff (i.e. different outputs) depending on the dryness of
    > the soil, the dryness of the soil has in fact the role of a state variable.
    > I think that such state variable could not be very useful is used as
    > input to the system.

    I don't agree. If you have no other way of estimating dryness, you should
    introduce it as an input and perform a parameter study over the space of
    all interesting combinations.

    My $0.02.

    Greg

    Hope this helps.

    Gregory E. Heath heath@ll.mit.edu The views expressed here are
    M.I.T. Lincoln Lab (781) 981-2815 not necessarily shared by
    Lexington, MA (781) 981-0908(FAX) M.I.T./LL or its sponsors
    02420-9185, USA

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