Zeno Gantner: Created page with "'''k-nearest neighbors''' ('''kNN''') are a classical method for recommender systems. Ratings or items are predicted by using the past ratings/items of the k most similar [[u..."

2011-06-06T17:13:32Z

Created page with "'''k-nearest neighbors''' ('''kNN''') are a classical method for recommender systems. Ratings or items are predicted by using the past ratings/items of the k most similar [[u..."

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'''k-nearest neighbors''' ('''kNN''') are a classical method for recommender systems.
Ratings or items are predicted by using the past ratings/items of the k most [[similar]] [[users]] and/or [[items]]. If the influence of the similar users/items is weighted by the similarity, all users/items may be used for the prediction. Popular similarity metrics are the [[Pearson correlation]] and the [[cosine similarity]].
Using the [[user-item]] matrix to compute the similarity is often called [[collaborative filtering]].
Computing the item similarities from the item attributes leads to [[content-based filtering]].

Adaptive kNN learns a similarity matrix that is particularly suitable for the recommendation task.

== See also ==
* [[collaborative filtering]]
* [[content-based filtering]]

== External links ==
* [[Wikipedia: k-nearest neighbor algorithm]]

[[Category: Method]]

KNN - Revision history

Zeno Gantner: Created page with "'''k-nearest neighbors''' ('''kNN''') are a classical method for recommender systems. Ratings or items are predicted by using the past ratings/items of the k most similar [[u..."