Dear Estevan:
On Fri, 26 Jul 2002, Estevam Rafael Hruschka Junior wrote:
> Dear all,
>
>
> when learning a BN from data, some algorithms (such as K2) are influenced by
> the variable order. And if this initial order is not the most appropriated,
> the results may be prejudiced. Trying to find this best order may be an
> exponential problem (when it's done by exhaustive search). One way to
> minimize this problem may be to prune the "less" significant variables. I've
> already implemented some initial tests and they showed that it's worthwhile
> to look for the best order when trying to improve the learning results.
>
>
> So I was wondering if there is any defined heuristic to deal with this
> problem.
CB uses a constraint-based algorithm to establish a partial or total order
on the variables, before using a Bayesian score. This seems to work very
well in practice. See the following two references:
@inProceedings{Singh93,
author = {Singh, Moninder and Valtorta, Marco},
title = {A New Algorithm for the Construction of {B}ayesian Network
Struc
tures from Data},
booktitle = {Proceedings of the Ninth Annual Conference on Uncertainty
in Art
ificial Intelligence (UAI-93)},
year = 1993,
month = {July},
address = {Washington DC},
pages = "259--264",
}
@article{Singh95,
author = {Singh, Moninder and Valtorta, Marco},
title = {Construction of Bayesian Belief Networks from Data: a
Brief
Survey and an Efficient Algorithm},
journal = {International Journal of Approximate Reasoning},
volume = 12,
number = 2,
pages = "111-131",
year = 1995,
month = {February},
}
>
>
> Thank you so much for your attention.
>
>
>
> Estevam.
>
> - -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
> Estevam Rafael Hruschka Junior
>
> [EMAIL PROTECTED]
> Curitiba PR. - Brazil.
>
>
Marco Valtorta Associate Professor
Department of Computer Science and Engineering
University of South Carolina
Columbia, SC 29208, U.S.A. http://www.cse.sc.edu/~mgv/
803.777-4641 fax:-3767 [EMAIL PROTECTED]
- ---------------------------------------------------------------------------
"Probability is not about numbers. It is about the structure of reasoning."
--Glenn Shafer
- ---------------------------------------------------------------------------
