Sets of approximating functions with finite Vapnik–Chervonenkis dimension for nearest-neighbors algorithms
► Reformulation of k-NN algorithm to alpha-NN ∗ algorithm (where alpha is a fraction). ► Establishing sets of functions for alpha-NN ∗, with finite capacity. ► Pointing out degrees of freedom for these sets. ► Proving theorems about dichotomies and VC-dimension for the proposed sets. According to a...
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| Veröffentlicht in: | Pattern recognition letters Jg. 32; H. 14; S. 1882 - 1893 |
|---|---|
| Hauptverfasser: | , |
| Format: | Journal Article |
| Sprache: | Englisch |
| Veröffentlicht: |
Amsterdam
Elsevier B.V
15.10.2011
Elsevier |
| Schlagworte: | |
| ISSN: | 0167-8655, 1872-7344 |
| Online-Zugang: | Volltext |
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| Zusammenfassung: | ► Reformulation of
k-NN algorithm to alpha-NN
∗ algorithm (where alpha is a fraction). ► Establishing sets of functions for alpha-NN
∗, with finite capacity. ► Pointing out degrees of freedom for these sets. ► Proving theorems about dichotomies and VC-dimension for the proposed sets.
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
α
∈
(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/
α⌋. 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. |
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| ISSN: | 0167-8655 1872-7344 |
| DOI: | 10.1016/j.patrec.2011.07.012 |