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AW: AW: DM: RE: Data Forms for Mining (Limit on variables)From: Frank Buckler Date: Fri, 26 May 2000 08:50:22 +0200 The vc-dimension tells how many example a specific learning algorithm can learn/represent. In order to achieve ANY generalisation you need more examples than the vc-dimension. The vc-dimension is determined by the number of inputs. For neural networks it is only possible to approximate the vc-dim. But for linear methods e.g. linear regression it is quite simple Dvc= input+1. If a linear algo needs to represent any linear relationship with 7000 vars appr. More than 10 000, you need for non-linear modelling MUCH more than 100 000 examples. The number of required examples depends primarily on the nonlinearities of the problem, not on the number of var's. The vc-dimension is only bound, which show conventionally that some case-studies have to produce noise or non- sense. All this shows the crucial task of statistical or manual based preselection and processing. All this is an result of the falsification principle in science theory. More on this in Vapnik, V, 1995, "nature of statistical learning theory" or try one of the papers related to Support-Vector-Mashines in http://svm.first.gmd.de Frank Frank Buckler ------------------------------------------------------------ University of Hanover Dep. Marketing II buckler@m2.uni-hannover.de -----Ursprüngliche Nachricht----- Von: owner-datamine-l@nautilus-sys.com [mailto:owner-datamine-l@nautilus-sys.com]Im Auftrag von H. Mark Hubey Gesendet: Mittwoch, 24. Mai 2000 21:42 An: datamine-l@nautilus-sys.com Betreff: Re: AW: DM: RE: Data Forms for Mining (Limit on variables) Frank Buckler wrote: > > Issue: Number of Inputs > > I'm surprised to hear that some guy's are using from thousand up to million > of inputs. > > There exist an upper bound on input-number determined by sample size. This > is advocated due to the VC-Dimension. I am new to this. What is "VC-dimension"? -- Mark Hubey, Professor Department of Computer Science Montclair State University http://www.csam.montclair.edu/~hubey
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