Paper: | SPTM-P10.10 |
Session: | Estimation |
Time: | Thursday, May 18, 16:30 - 18:30 |
Presentation: |
Poster
|
Topic: |
Signal Processing Theory and Methods: Detection, Estimation, Classification Theory and Applications |
Title: |
Low-Rank Variance Estimation in Large-Scale GMRF Models |
Authors: |
Dmitry Malioutov, Jason Johnson, Alan Willsky, Massachusetts Institute of Technology, United States |
Abstract: |
We consider the problem of variance estimation in large-scale Gauss-Markov random field (GMRF) models. While approximate mean estimates can be obtained efficiently for sparse GMRFs of very large size, computing the variances is a challenging problem. We propose a simple rank-reduced method which exploits the graph structure and the correlation length in the model to compute approximate variances with linear complexity in the number of nodes. The method has a separation length parameter trading off complexity versus estimation accuracy. For models with bounded correlation length, we efficiently compute provably accurate variance estimates. |