Since most algorithms for Bayesian Belief Network (BBN) creation require
discrete data, a method to convert continuous data into discrete is used
in a pre-processing step. An information-theoretic metric is used in a
recently published article by myself and Bruce Barton. The discretization
method can be extended to dynamically combine existing partitions when
creating a BBN, if a Minimum Descriptive Length (MDL) metric is used to
guide the BBN creation.
  This method does not rely on assumptions about the data distribution and
is intentionally designed to handle 'multi-modal' data distributions with
a minimal loss of information. 
 The reference is: 

  Clarke,E., and Barton,B., (2000), Entropy and MDL Discretization of
Continuous Variables for Bayesian Belief Networks. International Journal
of Intelligent Systems, 15, 61-92.

  Another relatively recent article on the same topic is:

  Monti,S., and Cooper,G., (1998), A Multivariate Method for Learning
Bayesian Networks from Mixed Data, Proc. Uncertainty in Artificial
Intelligence, ed. Cooper,G., and Moral,S., Morgan Kaufmann, S.F.

  I hope this helps.

  Ellis


On Thu, 6 Apr 2000, Zhu wrote:

> Hello all, 
> 
> Is there any algorithms of Bayesian Network to work directly on the
> mixture of continuous and categorical variables?
> 
> The classification problem that I am working on has 37 input variables, 15
> of them are categorical and the rest of them are continuous.  To my
> understanding, I need to discretize the continuous varibles in order to
> apply some commonly used algorithms (such as junction tree) to construct
> and estimate BNs.   Since a large portion of the input variables are
> continuous, I am afraid of loss of information by discretizing them.
> References and input on working directly on the mixture will
> be highly appreciated.  I would also like to have any comments and
> experiences on how much gain we can get from working on the mixture
> directly over transforming all variables into discrete.  Thanks.
> 
> 
> Best regards,
> 
> Julie
>   
> 

_____________________________________________________________________
  Ellis Clarke, Ph.D.; CSEE, University of Maryland Baltimore County;
  [EMAIL PROTECTED]
_____________________________________________________________________


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