Search found 179 matches

by mark
Thu Jan 06, 2011 4:45 am
Forum: GeNIe
Topic: Discretization
Replies: 3
Views: 8262

Re: Discretization

No, because in the extreme you will get one state for each value in the data set, which is probably not what you what. You'll have to experiment and somehow evaluate what works best.
by mark
Thu Jan 06, 2011 4:42 am
Forum: GeNIe
Topic: Feature Selection algorithm?
Replies: 2
Views: 5495

Re: Feature Selection algorithm?

Feature selection uses Greedy Thick Thinning (search forum for more info) to first greedily add features and then remove features that maximizes a Bayesian score function.
by mark
Sun Dec 12, 2010 4:23 am
Forum: GeNIe
Topic: Learning DBN parameters (transition probablilities) in GeNIe
Replies: 20
Views: 38238

Re: Learning DBN parameters (transition probablilities) in G

You can definitely learn these probabilities from data but you'll need time series data.
by mark
Sun Dec 12, 2010 4:20 am
Forum: GeNIe
Topic: Learning Bayesian Network From Data
Replies: 1
Views: 5364

Re: Learning Bayesian Network From Data

Is it possible there are no dependencies in the data (i.e., random)?
by mark
Fri Nov 19, 2010 12:49 am
Forum: SMILE
Topic: noisy-max question
Replies: 5
Views: 11043

Re: noisy-max question

What kind of noisyMax-specific code are you using for parameter learning? When I did some learning on a noisyMax network (in GeNIe) I got the impression that no special code was used. The reason is that after learning, when I saved the network, the noisyMax parameters in the file where replaced by ...
by mark
Thu Oct 21, 2010 4:22 pm
Forum: GeNIe
Topic: how to obtain mathematical equation of a network
Replies: 1
Views: 4786

Re: how to obtain mathematical equation of a network

Hint: The joint distribution is given by P(C,xi,yi,ti,xf,yf,tf)=P(yi)P(xi|yi)P(ti|yi)P(C|ti)P(tf|C)P(xf|C)P(yf|tf). All other probabilities can be derived from that. Does this help?
by mark
Tue Oct 12, 2010 9:39 pm
Forum: GeNIe
Topic: Learning Structure
Replies: 7
Views: 14153

Re: Learning Structure

PC is the only option for continuous data, otherwise you need to discretize.
by mark
Tue Oct 12, 2010 9:15 am
Forum: GeNIe
Topic: Learning Structure
Replies: 7
Views: 14153

Re: Learning Structure

* What is the new structure represent?
* How can i build BN from my data (with this new structure representation ), when my main purpose is finding dependency between
attributes?
The new structure denotes a direct dependency between variables when an edge exists, and edges are oriented if the ...
by mark
Wed Aug 04, 2010 6:06 am
Forum: SMILE
Topic: EM algorithm details
Replies: 1
Views: 5578

1. Your guess is correct.
2. It randomizes all the CPT parameters (but only if the equivalent sample size is zero).
by mark
Sun Mar 28, 2010 11:43 pm
Forum: GeNIe
Topic: Continuous variables
Replies: 23
Views: 68005

Since they are observed, they don't change when inference is performed. Beliefs of neighboring nodes will be updated.
by mark
Sun Mar 28, 2010 8:57 pm
Forum: GeNIe
Topic: Continuous variables
Replies: 23
Views: 68005

No, I believe this is still quite different. In case of Bayesian networks only one state can be true at a time but you may not know which one, hence the distributions. In case of a fuzzy Bayesian networks multiple states may be true to certain degrees at the same time, which is conceptually different.
by mark
Sat Mar 27, 2010 5:55 pm
Forum: GeNIe
Topic: Continuous variables
Replies: 23
Views: 68005

What is a fuzzy Bayesian network?

Hard evidence is observing the state of a node with probability 1. Soft evidence is observing a distribution over the states of a node.
by mark
Tue Jan 05, 2010 4:47 pm
Forum: GeNIe
Topic: learning new network
Replies: 3
Views: 11739

Please search the forum for explanations and references. If you still have questions, please let me know.
by mark
Fri Jun 19, 2009 8:31 am
Forum: SMILE
Topic: greedythickthinning, what is it exactly?
Replies: 7
Views: 18493

For standard greedy search you need a random starting position, this is not necessary for GreedyThickThinning.
by mark
Thu Jun 18, 2009 5:14 pm
Forum: SMILE
Topic: greedythickthinning, what is it exactly?
Replies: 7
Views: 18493

Yes, it's a greedy search algorithm that works in two stages.