Arnsholt

Welcome back

Hello... I noticed you've come back to wikipedia after about 6 months of being away. I suggest checkin up the Akkadian language article. I've completed the rest of the article and added a few tables and sections. Please if u have any additions, do so directly on the article. Take care--Xevorim (talk) 15:27, 22 June 2009 (UTC)

RE: Conditional Random Fields

I found the article hard to follow. I subsequently had to read a tutorial by Charles Elkan (http://cseweb.ucsd.edu/~elkan/254/) and the 2010 version of the Sutton-McCallum article to understand the subject.

I believe it is important to state the connection between Logistic Regression, Hidden Markov Models and Conditional Random Fields as illustrated in the Sutton and McCallum article. I.e., just as HMMs extend Naive-Bayes to sequential data, the commonest implementation of CRFs (linear-chain) extend Logistic Regression to sequential data - i.e., they are the discriminative counterpart of HMMs.

It may alsos be worth providing a practical example of their application - the Sutton/McCallum tutorial uses named entity recognition, but there are also lots of bioinformatics applications. The ability to handle a large number of features/variables while still retaining tractability is important to emphasize - a strength over HMMs, which are essentially univariate. (Successful attempts at using multi-variate HMMs generally use the trick of creating an artificial variable that is a uniquely determined composite of multiple categorical variables. e.g., if you have two categorical variables with M and N distinct values, you create a new variable with M*N possible values and use that in the HMM.

Prakash Nadkarni (talk) —Preceding undated comment added 22:10, 6 July 2011 (UTC).