Sets of approximating functions with finite Vapnik-Chervonenkis dimension for nearest-neighbors algorithms

  • Authors:
  • P. Klsk;M. Korzeń

  • Affiliations:
  • Department of Methods of Artificial Intelligence and Applied Mathematics, Westpomeranian University of Technology, Szczecin, Poland;Department of Methods of Artificial Intelligence and Applied Mathematics, Westpomeranian University of Technology, Szczecin, Poland

  • Venue:
  • Pattern Recognition Letters
  • Year:
  • 2011

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Abstract

According to a certain misconception sometimes met in the literature: for the nearest-neighbors algorithms there is no fixed hypothesis class of limited Vapnik-Chervonenkis dimension. In the paper a simple reformulation (not a modification) of the nearest-neighbors algorithm is shown where instead of a natural number k, a percentage @a@?(0,1) of nearest neighbors is used. Owing to this reformulation one can construct sets of approximating functions, which we prove to have finite VC dimension. In a special (but practical) case this dimension is equal to @?2/@a@?. It is also then possible to form a sequence of sets of functions with increasing VC dimension, and to perform complexity selection via cross-validation or similarly to the structural risk minimization framework. Results of such experiments are also presented.