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Article #34Re: How to improve decision tree classification model error rate?
From: Timothy Parkin
Date: Thu, 13 Jun 2002 01:55
Date: Thu, 13 Jun 2002 01:55
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3517 bytes
how about independent components analysis--- which allows for nonlinear relationships--- just wondering.... "Arthur J. Kendall" <Arthur.Kendall@verizon.net> wrote in message news:3D0748DB.E857635D@verizon.net... > It seems that you want to reduce each time series to a a few parameters and > cluster those parameters. > > The Classification Society of North America page > http://www.pitt.edu/~csna/ > might be of help. I have seen this kind of problem at past CSNA meetings. > Browse the abstracts etc. > > You might post a message on <class-l> describing your data and the kind of > questions you have. > > > Eric Bohlman wrote: > > > In sci.stat.math Alexander Sirotkin <demiurg@tau.ac.il> wrote: > > > There is an information in this data set that may current > > > classification model does not use. The model does not take into > > > account taht these 562 real predictor variables (not records !!!) > > > have order, meaning that the variables are not just x[1], x[2],..., x[561] > > > but it is important that x[3] comes after x[2] (because these variables > > > are actually samples from continues function). > > > > > what I'm trying to do, actually, is to build a classification model > > > using functions (sampled at 562 points) as independent variables ! > > > > Ah, you're saying that your independent variables are actually the values > > of a time series. In that case, some of your difficulty may be coming > > from the fact that they're so highly correlated that it's difficult to > > distinguish the weights that should be assigned them. > > > > It looks like you're really trying to estimate the coefficients of a > > finite-impulse-response filter whose output is then somehow quantized into > > 80-something not-necessarily-equal-sized steps. I'm not really sure how > > to deal with such a problem. One thing that's clear is that anything > > resembling classical discriminant analysis isn't going to work with your > > sample size of around 10,000, because it would require estimating around > > 45,000 parameters which is almost 5 times the number of independent > > observations you have. I also have a very strong hunch that your apparent > > "success" with stepwise methods is actually success at fitting the noise, > > rather than signal, in your data. >
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10d632,777798b8d4d7b811 X-Google-Attributes: gid10d632,public X-Google-Thread: fa931,777798b8d4d7b811 X-Google-Attributes: gidfa931,public X-Google-ArrivalTime: 2002-06-12 18:55:05 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!netnews.com!xfer02.netnews.com!newsfeed.zip.com.au!newsfeed.iinet.net.au!news.iinet.net.au!not-for-mail From: "Timothy Parkin" <tim32p@iinet.net.au> Newsgroups: sci.stat.math,aus.stats.s References: <adrouf$h81$1@mulga.cs.mu.OZ.AU> <mka9gukh228jdm993ht1erdo793j6f52ig@4ax.com> <dd39f296.0206111402.1284fba8@posting.google.com> <ae7gpn$2et$1@bob.news.rcn.net> <3D0748DB.E857635D@verizon.net> Subject: Re: How to improve decision tree classification model error rate? Date: Thu, 13 Jun 2002 09:55:27 +0800 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Lines: 56 Message-ID: <3d07fb48$0$14177@echo-01.iinet.net.au> NNTP-Posting-Host: i188-133.nv.iinet.net.au X-Trace: news.iinet.net.au 1023933256 14177 203.59.188.133