Friday, April 11, 2008

(Math) seminars during April 14-18

We have a seminar and a colloquium during April 14-18

Speaker: M. Boratynski,
University of Bari, Italy
Date and Time: Tuesday, April 15, 2008 at 4 p.m.

Title: ``Invariant tubular neighborhood theorem for affine
Venue: Ramanujan Hall


The topic of the talk is the algebraic geometry analogue of the
Invariant tubular neighborhood theorem which concerns the action
of compact Lie groups on differential manifolds.

Title: A graphical method to compare the efficiencies of cluster
randomized designs
Speaker: Prof. Siuli Mukhopadhyay
Department of Mathematics, IIT-B
Time: 3-4 pm
Date 15 April
Room 113


The purpose of this talk is to compare efficiencies of several cluster
randomized designs using the method of quantile dispersion graphs (QDGs).
cluster randomized design is considered whenever
subjects are randomized at a group level but analyzed at the individual
level. A prior knowledge of
the correlation existing between subjects within the same cluster is
necessary to design these cluster
randomized trials. Using the QDG approach we are able to compare several
cluster randomized designs
without requiring any information on the intracluster correlation. For a
given design, quantiles of
the power function are obtained for several effect sizes. The quantiles
depend on the intracluster
correlation present in the model. The dispersion of these quantiles over
space of the unknown
intracluster correlation is determined, and then depicted by the QDGs. Two
applications of the
proposed methodology are presented.

Tony J. Puthenpurakal