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|    Message 1,026 of 1,954    |
|    Ted Dunning to All    |
|    Re: Transduction with regression    |
|    03 May 06 01:56:07    |
      From: ted.dunning@gmail.com              Actually, the MASS book is about software, but it has a good intro to       resistant estimators and I believe it has good links to the literature.        I may have pointed you to the software companion site, but you can get       to the book from there.              Also, the BUGS system is all about Bayesian inference of various sorts,       but it can definitely be used for regression. The idea is that you       have a model with unknown parameters that have prior distributions and       computing the posterior is either inference or regression. In the       simplest case of single variable linear regression, you might have               y_i = a x_i + b + noise              where a and b have relative uninformative priors and the noise is       normal with unknown variance and zero mean. The variance on the noise       would then also have a relatively uninformative prior. Given       observations of x_i and y_i, you can find a posterior distribution of       a, b and the variance on the noise. This is regression, plain and       simple. In this example, knowing that value of some x without a       corresponding y (or vice versa) doesn't tell you very much, but if       there were multiple x's on the right hand side and you were told the       values of four of them plus the corrresponding value of y, then you       begin to have something. Likewise, if you assume that the x's are       sampling from a lower dimension sub-space, then having x's without y's       can inform you about that sub-space and thus constrain the regression.              The BUGS sites have good links to literature on graphical models which       is the currently fashionable idiom for expressing these sorts of       things.              The Mackay site talks a lot about Bayesian inference, but neural       networks are simply a form of regression and he talks quite a bit about       some interesting approximation approaches for using neural networks       that allow one to approximate the posterior distribution of the       coefficients.              I know that these links don't directly bear on transduction, but I do       think that they would give you an interesting alternative nomenclature       that would open up alternative sets of literature (written by all the       guys who don't use the word transduction). They also would provide you       some opportunities to possibly break some new ground in your particular       problem area.              [ comp.ai is moderated. To submit, just post and be patient, or if ]       [ that fails mail your article to |
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