12,037 research outputs found
Perceptual bistability in auditory streaming: how much do stimulus features matter?
The auditory two-tone streaming paradigm has been used extensively to study the mechanisms that underlie the decomposition of the auditory input into coherent sound sequences. Using longer tone sequences than usual in the literature, we show that listeners hold their ïŹrst percept of the sound seÂŹquence for a relatively long period, after which perception switches between two or more alternative sound organizations, each held on average for a much shorter duration. The ïŹrst percept also differs from subsequent ones in that stimulus parameters inïŹuence its quality and duration to a far greater degree than the subsequent ones. We propose an account of auditory streaming in terms of rivalry beÂŹtween competing temporal associations based on two sets of processes. The formation of associations (discovery of alternative interpretations) mainly affects the ïŹrst percept by determining which sound group is discovered ïŹrst and how long it takes for alternative groups to be established. In contrast, subÂŹsequent percepts arise from stochastic switching between the alternatives, the dynamics of which are determined by competitive interactions between the set of coexisting interpretations
Statistical Inference for Partially Observed Markov Processes via the R Package pomp
Partially observed Markov process (POMP) models, also known as hidden Markov
models or state space models, are ubiquitous tools for time series analysis.
The R package pomp provides a very flexible framework for Monte Carlo
statistical investigations using nonlinear, non-Gaussian POMP models. A range
of modern statistical methods for POMP models have been implemented in this
framework including sequential Monte Carlo, iterated filtering, particle Markov
chain Monte Carlo, approximate Bayesian computation, maximum synthetic
likelihood estimation, nonlinear forecasting, and trajectory matching. In this
paper, we demonstrate the application of these methodologies using some simple
toy problems. We also illustrate the specification of more complex POMP models,
using a nonlinear epidemiological model with a discrete population,
seasonality, and extra-demographic stochasticity. We discuss the specification
of user-defined models and the development of additional methods within the
programming environment provided by pomp.Comment: In press at the Journal of Statistical Software. A version of this
paper is provided at the pomp package website: http://kingaa.github.io/pom
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