perl.ai...Re: text categorization with SVM and NaiveBayes by Ken Williams- January 9, 2007 On Jan 8, 2007, at 10:51 AM, Tom Fawcett wrote:> Just to add a note here: Ken is correct -- both NB and SVMs are > known to be rather poor at providing accurate probabilities. Their > scores tend to be too extreme. Producing good probabilities from > these scores is called calibrating the classifier, and it&39;s more > complex than just taking a root of the score. There are several > methods for calibrating scores. The good news is that there&39;s an > effective...http://www.nntp.perl.org/group/perl.ai/2007/01/msg561.html Re: text categorization with SVM and NaiveBayes by Tom Fawcett- January 8, 2007 On Jan 7, 2007, at 9:23 PM, Ken Williams wrote:>> I would happily ignore all this and use NB, but it has one major >> flaw.>> "The winner takes it all", the first result returned is way too far>> (as in distance :)) from the others, which isn&39;t exactly accurate if>> one cares of a balanced results pool. I don&39;t know whether this is an>> implementation problem - I poked around the rescale() function in>> Util.pm with no real success - or.http://www.nntp.perl.org/group/perl.ai/2007/01/msg560.html Re: text categorization with SVM and NaiveBayes by Ken Williams- January 8, 2007 On Jan 5, 2007, at 7:10 AM, zgrim wrote:> So, back to my dilemmas. :) The results are puzzling, as many of the> research papers on the subject I&39;ve consulted say that SVM is> supposedly the best algorithm for this task. The radial kernel should> give the best results, for empirical-found values of gamma and C.This may be an issue with your corpus - I quite often find that when I don&39;t have enough training data for the SVM to pick up on the "truth" patterns, or...http://www.nntp.perl.org/group/perl.ai/2007/01/msg559.html text categorization with SVM and NaiveBayes by zgrim- January 5, 2007 Hello, I am "playing" with the task of automated text categorization andinevitably hit a few dilemmas. I have tried different combinations ofSVM and NaiveBayes, here are some results:- algorithm::svm (single world, through AI::Categorizer) 92%accuracy (with the linear kernel, the radial one has bellow 10% withall sorts of values tried for gamma and c)- algorithm::svmlight ( nr. of categories worlds - each trainedagainst the others ) 62% in ranking mode- algorithm::naivebayes (one...http://www.nntp.perl.org/group/perl.ai/2007/01/msg558.html Creating Collection of uncategorized data by Alan Gibson- January 4, 2007 Hello,First post to this list. Im beginning a project that will useautomated text classification to classify congressional bills andAI::Categorizer looks like the best framework to use. However, Imhitting a snag on what should be a simple operation.I train an svm classifier on 1000 documents; this operation goes fine.I then try to create an instance of AI::Categorizer::Collection::Filescontaining 5 unclassified documents. I supply only the path becausethe 5 documents are not yet categorized: .http://www.nntp.perl.org/group/perl.ai/2007/01/msg557.html Re: ai::categorize samples by Russell Foltz-Smith- January 4, 2007 Thanks, that&39;s helpful. It&39;s very difficult to find this corpus, especially in most of the existing documentation on AI::Categorizer.Thanks, Dr. Math.RussKen Williams wrote:> On Jan 2, 2007, at 8:53 PM, Russell Foltz-Smith wrote:>>> Does someone have an examples category text file that works with the>> demo.pl>> Yup, you can download it from > http:campstaff.comkenreuters-21578.tar.gz .>>>> Also, does anyone know of an onlineweb service...http://www.nntp.perl.org/group/perl.ai/2007/01/msg556.html Re: ai::categorize samples by Ken Williams- January 4, 2007 On Jan 2, 2007, at 8:53 PM, Russell Foltz-Smith wrote:> Does someone have an examples category text file that works with the> demo.plYup, you can download it from http:campstaff.comken reuters-21578.tar.gz .> Also, does anyone know of an onlineweb service implementation for web> pagesurls to categorize them into dmoz categoriesNot I. -Kenhttp://www.nntp.perl.org/group/perl.ai/2007/01/msg555.html ai::categorize samples by Russell Foltz-Smith- January 3, 2007 Does someone have an examples category text file that works with the demo.plAlso, does anyone know of an onlineweb service implementation for web pagesurls to categorize them into dmoz categoriesRuss Smithhttp://www.nntp.perl.org/group/perl.ai/2007/01/msg554.html ai::categorize samples by Russell Foltz-Smith- January 2, 2007 Does someone have an examples category text file that works with thedemo.plAlso, does anyone know of an onlineweb service implementation for webpagesurls to categorize them into dmoz categoriesRuss Smithhttp://www.nntp.perl.org/group/perl.ai/2007/01/msg553.html |