Needles and straw in haystacks: Empirical Bayes estimates of possibly sparse sequences

By Iain M. Johnstone, Bernard Walter Silverman. 2004

517 citations recorded by the source corpus.

An empirical Bayes approach to the estimation of possibly sparse sequences observed in Gaussian white noise is set out and investigated. The prior considered is a mixture of an atom of probability at zero and a heavy-tailed density y, with the mixing weight chosen by marginal maximum likelihood, in the hope of adapting between sparse and dense sequences. If estimation is then carried out using the posterior median, this is a random thresholding procedure. Other thresholding rules employing the same threshold can also be used. Probability bounds on the threshold chosen by the marginal maximum likelihood approach lead to overall risk bounds over classes of signal sequences of length n, allowing for sparsity of various kinds and degrees. The signal classes considered are nearly black sequences where only a proportion η is allowed to be nonzero, and sequences with normalized p norm bounded by η, for η > 0 and 0 1. Simulations show excellent performance. For appropriately chosen functions y, the method is computationally tractable and software is available. The extension to a modified thresholding method relevant to the estimation of very sparse sequences is also considered.

Subfields: Artificial Intelligence, Computer Vision and Pattern Recognition, Signal Processing

View Paper: https://www.semanticscholar.org/paper/ac2ebdb7fc572b75f4f8a8afb6abd104bb9a233b

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In Artificial Intelligence

  1. A. van der Vaart
  2. Stéphanie van der Pas
  3. Botond Szab'o
  4. Judith Rousseau
  5. I. Castillo
  6. David B. Dunson
  7. Stephen G. Walker
  8. Cun-Hui Zhang

In Computer Vision and Pattern Recognition

  1. David L. Donoho
  2. Michael Elad
  3. Jean-Luc Starck
  4. A. van der Vaart
  5. David B. Dunson
  6. Guy P. Nason
  7. Yaakov Tsaig
  8. Botond Szab'o

In Signal Processing

  1. Cun-Hui Zhang
  2. A. van der Vaart
  3. David L. Donoho
  4. Guy P. Nason
  5. Botond Szab'o
  6. Wenhua Jiang
  7. Stéphanie van der Pas
  8. Merlise A. Clyde

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