Fei Sha

  1. Learning Discriminative Metrics via Generative Models and Kernel Learning.

    Authors: Fei Sha, Yuan Shi, Yung-Kyun Noh, Daniel D. Lee
    Subjects: Learning
    Abstract

    Metrics specifying distances between data points can be learned in a
    discriminative manner or from generative models. In this paper, we show how to
    unify generative and discriminative learning of metrics via a kernel learning
    framework. Specifically, we learn local metrics optimized from parametric
    generative models. These are then used as base kernels to construct a global
    kernel that minimizes a discriminative training criterion. We consider both
    linear and nonlinear combinations of local metric kernels.

  2. Rapid Feature Learning with Stacked Linear Denoisers.

    Authors: Zhixiang Eddie Xu, Kilian Q. Weinberger, Fei Sha
    Subjects: Learning
    Abstract

    We investigate unsupervised pre-training of deep architectures as feature
    generators for "shallow" classifiers. Stacked Denoising Autoencoders (SdA),
    when used as feature pre-processing tools for SVM classification, can lead to
    significant improvements in accuracy - however, at the price of a substantial
    increase in computational cost. In this paper we create a simple algorithm
    which mimics the layer by layer training of SdAs. However, in contrast to SdAs,
    our algorithm requires no training through gradient descent as the parameters
    can be computed in closed-form.

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