Séance Séminaire

Séminaire de Probabilités et Statistique

A model for phyllochron analysis from interval censored measurements

Plant development consists in various synchronised processes. In particular, the process of leaf apperance or phyllochron, characterised by the time of appearance of each leaf, is often studied as an easily observed indicator. In this talk, I will present a statistical model for phyllochron with independent time intervals between leaves, when the times of leaf appearance are interval censored, estimated via an EM-type algorithm. First of all, we have considered a Gaussian parametrisation to take advantage of existing generator from the truncated multivariate normal distribution. A more general parametrisation can be considered using the framework of semi-Markov models ; then the forward-backward algorithm, originally developed for hidden semi-Markov models, can be adapted to the interval censoring context. This new parametrisation allows more flexible parametrisation, notably including climatic longitudinal covariate. The semi-Markov approach is currently a work in progress.

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