1,199 research outputs found
Estimating Spatial Econometrics Models with Integrated Nested Laplace Approximation
Integrated Nested Laplace Approximation provides a fast and effective method
for marginal inference on Bayesian hierarchical models. This methodology has
been implemented in the R-INLA package which permits INLA to be used from
within R statistical software. Although INLA is implemented as a general
methodology, its use in practice is limited to the models implemented in the
R-INLA package.
Spatial autoregressive models are widely used in spatial econometrics but
have until now been missing from the R-INLA package. In this paper, we describe
the implementation and application of a new class of latent models in INLA made
available through R-INLA. This new latent class implements a standard spatial
lag model, which is widely used and that can be used to build more complex
models in spatial econometrics.
The implementation of this latent model in R-INLA also means that all the
other features of INLA can be used for model fitting, model selection and
inference in spatial econometrics, as will be shown in this paper. Finally, we
will illustrate the use of this new latent model and its applications with two
datasets based on Gaussian and binary outcomes
Computer model calibration with large non-stationary spatial outputs: application to the calibration of a climate model
Bayesian calibration of computer models tunes unknown input parameters by
comparing outputs with observations. For model outputs that are distributed
over space, this becomes computationally expensive because of the output size.
To overcome this challenge, we employ a basis representation of the model
outputs and observations: we match these decompositions to carry out the
calibration efficiently. In the second step, we incorporate the non-stationary
behaviour, in terms of spatial variations of both variance and correlations, in
the calibration. We insert two integrated nested Laplace
approximation-stochastic partial differential equation parameters into the
calibration. A synthetic example and a climate model illustration highlight the
benefits of our approach
The Integrated nested Laplace approximation for fitting models with multivariate response
This paper introduces a Laplace approximation to Bayesian inference in
regression models for multivariate response variables. We focus on Dirichlet
regression models, which can be used to analyze a set of variables on a simplex
exhibiting skewness and heteroscedasticity, without having to transform the
data. These data, which mainly consist of proportions or percentages of
disjoint categories, are widely known as compositional data and are common in
areas such as ecology, geology, and psychology. We provide both the theoretical
foundations and a description of how this Laplace approximation can be
implemented in the case of Dirichlet regression. The paper also introduces the
package dirinla in the R-language that extends the INLA package, which can not
deal directly with multivariate likelihoods like the Dirichlet likelihood.
Simulation studies are presented to validate the good behaviour of the proposed
method, while a real data case-study is used to show how this approach can be
applied
Designing Proposal Distributions for Particle Filters using Integrated Nested Laplace Approximation
State-space models are used to describe and analyse dynamical systems. They
are ubiquitously used in many scientific fields such as signal processing,
finance and ecology to name a few. Particle filters are popular inferential
methods used for state-space methods. Integrated Nested Laplace Approximation
(INLA), an approximate Bayesian inference method, can also be used for this
kind of models in case the transition distribution is Gaussian. We present a
way to use this framework in order to approximate the particle filter's
proposal distribution that incorporates information about the observations,
parameters and the previous latent variables. Further, we demonstrate the
performance of this proposal on data simulated from a Poisson state-space model
used for count data. We also show how INLA can be used to estimate the
parameters of certain state-space models (a task that is often challenging)
that would be used for Sequential Monte Carlo algorithms.Comment: 13 pages, 4 figure
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