125,386 research outputs found
Iterative Temporal Learning and Prediction with the Sparse Online Echo State Gaussian Process
Abstract—In this work, we contribute the online echo state gaussian process (OESGP), a novel Bayesian-based online method that is capable of iteratively learning complex temporal dy-namics and producing predictive distributions (instead of point predictions). Our method can be seen as a combination of the echo state network with a sparse approximation of Gaussian processes (GPs). Extensive experiments on the one-step prediction task on well-known benchmark problems show that OESGP produced statistically superior results to current online ESNs and state-of-the-art regression methods. In addition, we characterise the benefits (and drawbacks) associated with the considered online methods, specifically with regards to the trade-off between computational cost and accuracy. For a high-dimensional action recognition task, we demonstrate that OESGP produces high accuracies comparable to a recently published graphical model, while being fast enough for real-time interactive scenarios. I
Intrinsic Gaussian processes on complex constrained domains
We propose a class of intrinsic Gaussian processes (in-GPs) for
interpolation, regression and classification on manifolds with a primary focus
on complex constrained domains or irregular shaped spaces arising as subsets or
submanifolds of R, R2, R3 and beyond. For example, in-GPs can accommodate
spatial domains arising as complex subsets of Euclidean space. in-GPs respect
the potentially complex boundary or interior conditions as well as the
intrinsic geometry of the spaces. The key novelty of the proposed approach is
to utilise the relationship between heat kernels and the transition density of
Brownian motion on manifolds for constructing and approximating valid and
computationally feasible covariance kernels. This enables in-GPs to be
practically applied in great generality, while existing approaches for
smoothing on constrained domains are limited to simple special cases. The broad
utilities of the in-GP approach is illustrated through simulation studies and
data examples
Gaussian Process Modelling for Improved Resolution in Faraday Depth Reconstruction
The incomplete sampling of data in complex polarization measurements from
radio telescopes negatively affects both the rotation measure (RM) transfer
function and the Faraday depth spectra derived from these data. Such gaps in
polarization data are mostly caused by flagging of radio frequency interference
and their effects worsen as the percentage of missing data increases. In this
paper we present a novel method for inferring missing polarization data based
on Gaussian processes (GPs). Gaussian processes are stochastic processes that
enable us to encode prior knowledge in our models. They also provide a
comprehensive way of incorporating and quantifying uncertainties in regression
modelling. In addition to providing non-parametric model estimates for missing
values, we also demonstrate that Gaussian process modelling can be used for
recovering rotation measure values directly from complex polarization data, and
that inferring missing polarization data using this probabilistic method
improves the resolution of reconstructed Faraday depth spectra.Comment: 16 pages, 10 figures, submitted to MNRA
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