an adaptive nearest neighbor rule for classification
play

An adaptive nearest neighbor rule for classification Akshay - PowerPoint PPT Presentation

An adaptive nearest neighbor rule for classification Akshay Balsubramani, Stanford Sanjoy Dasgupta, UCSD Yoav Freund, UCSD Shay Moran, Google AI Princeton Main Idea: Modify k -NN Algorithm by Choosing k Adaptively for Each Query Classical


  1. An adaptive nearest neighbor rule for classification Akshay Balsubramani, Stanford Sanjoy Dasgupta, UCSD Yoav Freund, UCSD Shay Moran, Google AI Princeton

  2. Main Idea: Modify k -NN Algorithm by Choosing k Adaptively for Each Query • Classical k -NN: classify x by the majority vote of its k nearest in the training set. x is the green point in the middle. The label assigned to x is determined by its k nearest neighbors (inside the big circle, in this example k =13+12=25 )

  3. Main Idea: Modify k -NN Algorithm by Choosing k Adaptively for Each Query • Adaptive k -NN: • Iterate over the neighbors of x from nearest to furthest and query their labels. • If one of the label-classes obtains a significant majority then exit the loop and use this label to classify x . Points x that are far from the boundary observe a significant Points x that are close to the boundary require querying a large number of neighbors advantage after querying a small number of neighbors

  4. Main Result s Theoretical Results 1. Adaptive k-NN rule is consistent (i.e. achieves Bayes optimality in the limit). 2. Instance-dependent generalization bounds Number of examples required to classify x correctly depends on its “local- • margin” (a formal notion introduced in the paper). Points far from the boundary are correctly classified fast. • Practical Results 1. Adaptive k -NN rule is competitive with Classical k -NN with the best choice of k Thus, this method circumvents the need to tune the meta-parameter k. •

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend