Article available by ftp

[S.B. Holden]

The following technical report is available by anonymous ftp from the
archive of the Speech, Vision and Robotics Group at the Cambridge
University Engineering Department. It is accepted for publication 
in "Neural Computation". 

      On the Practical Applicability of VC Dimension Bounds

              Sean B. Holden and Mahesan Niranjan

             Technical Report CUED/F-INFENG/TR.155

                        October 12, 1994

	    Cambridge University Engineering Department 
		        Trumpington Street 
		        Cambridge CB2 1PZ 
			     England 


                             Abstract

This article addresses the question of whether some recent 
Vapnik-Chervonenkis (VC) dimension based bounds on sample complexity 
can be regarded as a practical design tool. Specifically, we are 
interested in bounds on the sample complexity for the problem of 
training a pattern classifier such that we can expect it to perform 
valid generalization. Early results using the VC dimension, while 
being extremely powerful, suffered from the fact that their sample 
complexity predictions were rather impractical. More recent results 
have begun to improve the situation by attempting to take specific 
account of the precise algorithm used to train the classifier. We 
perform a series of experiments based on a task involving the 
classification of sets of vowel formant frequencies. The results 
of these experiments indicate that the more recent theories provide 
sample complexity predictions that are significantly more applicable 
in practice than those provided by earlier theories; however, we 
also find that the recent theories still have significant shortcomings. 


************************ How to obtain a copy ************************

a) Via FTP:

unix> ftp svr-ftp.eng.cam.ac.uk
Name: anonymous
Password: (type your email address)
ftp> cd reports
ftp> binary
ftp> get holden_tr155.ps.Z
ftp> quit
unix> uncompress holden_tr155.ps.Z
unix> lpr holden_tr155.ps (or however you print PostScript)

The report is 22 pages in length. 

b) Via postal mail:

Request a hardcopy from

Dr. Sean B. Holden,
Cambridge University Engineering Department, 
Trumpington Street, 
Cambridge CB2 1PZ,
England.

or email me: sbh at eng.cam.ac.uk