REMINDER:
FIRST JOINT WARWICK-OXFORD STATISTICS SEMINAR
The first joint Warwick-Oxford Statistics seminar will take place
Thursday, February 8, 2007.
The programme is as follows.
2:30 Persi Diaconis (Stanford): Looking at discrete data using Markov chains
Abstract: Discrete data: contingency tables, collections of rankings or
graphs, bounds. We introduce a generalization of the usual spectral
analysis and the analysis of variance to do exploratory analysis of such
data. This extends Classical ideas of partitioning chi-square. It is easy
to adapt to looking at residuals from complex models. All of this is joint
work with Julia Saltzman.
3:45 - 4:15 Tea
4:15 Tom Snijders (Oxford and Groningen): Statistical methods for social
network dynamics
Abstract: A fundamental data type for representing social networks,
defined as
structures of ties between social actors, is the directed graph (digraph).
Nodes in the graph represent social actors, while arcs (directed lines)
represent the ties between them. Usually in social network analysis such
data types are considered with a fixed node set and a random arc set. The
dependence structures between arcs, e.g. tendencies to transitivity of
ties, lead to complications in modelling such data. A family of
probability models will be presented for longitudinal social network data:
actor-oriented models, based on assumptions about actors trying to
optimize their situation with very limited foresight. Such assumptions
often make sense as a simple approximation to social science ideas about
network dynamics. Two methods of estimation will be discussed. The first
is a method of moments, the second the maximum likelihood method. Both can
be implemented by Markov chain Monte Carlo methods. Illustrations will be
given by means of a few examples, with some attention paid to the
practical implementation. Some recent work and open problems will also be
mentioned.
5:30 Reception.
The event takes place at the
Mary Ogilvie Lecture Theatre, St Anne’s College, Woodstock Road, Oxford.
For directions see http://www.stannes.ox.ac.uk/about/how_to_find_us.html.
All welcome!
Gesine Reinert
David Cox
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