[Statlist] Next talk: Friday, February 22, 2013 with Thanh Mai Pham Ngoc, Université de Paris Sud Orsay

[Cecilia Rey]

ETH and University of Zurich

Organisers:
Proff. P. Bühlmann - L. Held - H.R. Kuensch - M. Maathuis - S. van de Geer - M. Wolf 

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We are glad to announce the following talk

Friday, February 22, 2013 -  15.15h  ETH Zurich HG G 19.1
with Thanh Mai Pham Ngoc, Université de Paris Sud Orsay

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Title:
Goodness of fit tests for noisy directional data

Abstract:
In astrophysics,a burning issue consists in understanding the behaviour of the so-called UUltra High Energy Cosmic Rays (UHECR). These latter are cosmic rays with an extreme kinetic energy and the rarest particles in the universe. The source of those most energetic particles remains a mystery. Finding out more about the law of probability of those incoming directions is crucial to gain an insight into the mechanisms generating the UHECR. 
Astrophysicists have at their disposal directional data which are measurements of the incoming directions of the UHECR on Earth. Unfortunately their trajectories are deflected by Galactic and intergalactic fields. A first way to model the deflection in the incoming directions can be done thanks to the following model with random rotations : Zi =εiXi, i=1,...,N We define a nonparametric test procedure to distinguish H0 : ”the density f of Xi is the uniform density f0 on the sphere” and H1. we show that an adaptive procedure cannot have a faster rate of separation than ψad(s) = (N/loglog(N))−2s/ (2s+2ν+1) and we provide a procedure which reaches this rate. We illustrate the theory by implementing our test procedure for 
various kinds of noise on SO(3) and by comparing it to other procedures. Applications to real data in astrophysics and paleomagnetism are provided.

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This abstract is also to be found under the following link: http://stat.ethz.ch/talks/research_seminar

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