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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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TITLE: Emulating Computer Simulators Using Compactly Supported Correlation Functions
SPEAKER: Derek Bingham
ABSTRACT:
Statistical emulators of computer simulators have proven to be useful in a variety of applications. However, a widely adopted model for building these emulators, using a Gaussian process distribution with strictly positive correlation function, can be computationally intractable when the number of evaluated input values is large. We propose a modification of this model that uses a combination of low-order regression terms and compactly supported correlation functions to recreate the desired predictive behavior of the simulator at a fraction of the computational cost. Following the usual approach of taking the correlation to be a product of correlations in each input dimension, we show how to impose restrictions on the range of each correlation, giving sparsity, while also allowing the ranges to trade off against one another in a data-adaptive way, thereby giving good predictive performance when the data are non-isotropic. We illustrate the method using data from a computer simulator of photometric red-shift.
