
Martin's
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Research
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STAT270
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Martin
Hazelton's webpage
Contact
me
martin.hazelton
AT otago.ac.nz
Department
of Mathematics and Statistics
University of Otago
Dunedin
New Zealand
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Martin
Hazelton's
Personal Webpage
About
Me
Hello and welcome to my webpage. I am Professor of
Statistics in the Department
of Mathematics and Statistics at the University
of Otago, in beautiful
Dunedin, New Zealand Aotearoa.
For
Current Otago Students
For information on papers that I currently teach, see the
paper codes under the Teaching heading in the panel on the
left.
If you are looking for advice on which statistics paper(s)
to take, then feel free to contact
me. If you are considering doing Honours or a PhD
in Statistics and think that you might like to be supervised
by me, then read about my research below.
About
My
Research
I have a variety of research interests. These include:
Smoothing
Methods
I have long been interested in kernel smoothing problems,
and in particular spatially adaptive methods for
multivariate data. Other areas of interest include kernel
deconvolution problems and constrained spline smoothing.
Spatial Statistics
A spatial point pattern is a dataset comprising the
locations of things or events. A major focus of my research
at present is developing better tools for model and
inference for spatial patterns. Most recently I have been
considering replicated point patterns, where multiple
observations are taken on individuals or regions, e.g.
locations of cells in repeated biopsies on multiple
patients, or locations of animals at various sites through
time. This work is in collaboration with Tilman
Davies, Adrian
Baddeley, Bethany
Macdonald, Ege
Rubak, and Rasmus
Waagerpetersen.
Statistical Modelling and Inference in Transportation
Science
Transportation science
generates a huge range of fascinating problems. I'm
focused on network tomography (in essence, statistical
methods for learning about high dimensional properties
of network traffic flows based on lower dimensional
observations), and modelling and inference for
day-to-day dynamic traffic networks.
Statistical Linear Inverse Problems and Z-Polytope
Sampling
Statistical linear inverse
problems are characterized by the linear system
y = Ax
where y
is a vector of observed data and x
is the variable of principal interest. The
configuration matrix A typically has (many) more columns
than rows, so that the linear system is
under-determined. A classic example is network
tomography, where we want to know about traffic flows x
on paths through the network but we observe only traffic
counts y
at various network locations.
Other examples with the same structure include
(re)sampling entries of a contingency table conditional
on various marginal totals, counts of individual animals
in capture-recapture experiments in ecology where
misidentification may occur (so that the true counts x
differ from the observed counts y),
and assessment of items for biosecurity risk under
stratified sampling.
When the data are counts, the observations y
constrain the variables of interest x
to lie in a Z-polytope - that is, the grid of integer
valued coordinates (yellow dots in the figure to the
right) within a multidimensional polyhedron. Practical
methods of statistical inference (like MCMC) require
that we sample vectors x
lying in this Z-polytope. This is typically done using a
random walk. The problem then is to construct a random
walk that traverses the Z-polytope efficiently and yet
always remains within its bounds. It turns out that this
is a hard problem!
I'm working on this topic with PhD student Linus Fromm,
and studying applications to biosecurity surveillance
with Andrew
Robinson.
Other Research
Topics
In addition to these medical
areas, I have a general interest in the application of
statistical methods. Indeed, one of the great things
about working in statistics is that I've had the
opportunity to look at a diverse range of intriguing
problems from a wide variety of areas, from archaeology,
to finance, to zoology.
Other
Stuff
Awards
I am an honorary life member of was the New
Zealand Statistical Association, and was the recipient
of the 2014 Littlejohn
Research Award, the Association's premier research
award. I was the 2025 E.A.
Cornish Lecturer.
Editorial
I was Editor-in-Chief of the Australian
and New Zealand Journal of Statistics from
2019-2025.
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