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Feature learning

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Feature learning is a set of techniques in machine learning that learn a transformation of "raw" inputs to a representation that can be effectively exploited in a supervised learning task such as classification. Feature learning algorithms themselves may be either unsupervised or supervised, and include autoencoders,[1], dictionary learning, restricted Boltzmann machines[1] and vector quantization using k-means clustering.[2][1]

Multilayer neural networks can also be considered to perform feature learning, since they learn a representation of their input at the hidden layer(s) which is subsequently used for classification or regression at the output layer. (By contrast, kernel methods such as the support vector machine compute a fixed transformation of their inputs by means of a kernel function, and do not perform feature learning.)

References

  1. ^ a b c Coates, Adam; Lee, Honglak; Ng, Andrew Y. (2011). An analysis of single-layer networks in unsupervised feature learning (PDF). International Conference on Artificial Intelligence and Statistics (AISTATS).
  2. ^ Csurka, Gabriella; Dance, Christopher C.; Fan, Lixin; Willamowski, Jutta; Bray, Cédric (2004). Visual categorization with bags of keypoints (PDF). ECCV Workshop on Statistical Learning in Computer Vision.