Differential geometry in 10 slides

Partha Niyogi's very lucid talk entitled Geometric Methods and Manifold Learning includes a brief and very basic introduction to differential geometry(starts at t=40:49) which I found helpful.

This was part of the Machine Learning Workshop I attended at the University of Chicago last June (MLSS'09). There were several other talks and tutorials of note. I especially enjoyed Emmanuel Candes' talk on sparse signal recovery. The talks are available at the videolectures website.

ISBI 2010

I'll be in Rotterdam in mid-April to present our paper entitled A Comprehensive Riemannian Framework for the Analysis of White Matter Fiber Tracts at the ISBI conference. This is the abstract:

A quantitative analysis of white matter fibers is based on different physical features (shape, scale, orientation and position) of the fibers, depending on the specific application. Due to the different properties of these features, one usually designs different metrics and spaces to treat them individually. We propose a comprehensive Riemannian framework that allows for a joint analysis of these features in a consistent manner. For each feature combination, we provide a formula for the distance, i.e. quantification of differences between fibers and a formula for geodesics, i.e. optimal deformations of fibers into each other. We illustrate this framework in the context of clustering fiber tracts from the corpus callosum and study the results from different combinations of features.

This is work I did with Anuj Srivastava and his student Sebastian Kurtek.

India Unbound

Dense Delhi fog followed me to Gwalior, Jhansi, Orchha--everywhere it seems, even France. I spent most of the first week of the new year in and out of airports and railway stations.
But this post is not about the long journey back to Rennes. India Unbound, Gurucharan Das' personal account of the socio-economic history of post-independence India is a compelling read. The story of a Punjabi family with roots on the other side of the Radcliffe divide and their middle class aspirations annotate discussions on economic policy. What could be dry chapters on Nehru, Shastri and the never-ending Gandhi line are brought to life with vignettes that have a "I was there" ring of authenticity.
It is this story telling that makes this book different from others. It is as easy to read as a well-researched work of fiction in the style of Amitav Ghosh.

USA yesterday, France today, India tomorrow

When I board the plane for India next week, and hopefully before I grow web feet, it will be the third country and continent I will have visited in less than a month. This itinerant researcher travels easily in time and space and culture only because I take my internet bubble with me everywhere. I am so completely entertained and enthralled by Kishore's hijinks, I could be anywhere and want for nothing.

USA yesterday, France today

The interlude is now over and I am back to overcast Rennes. A world away in the Florida bible belt, Anuj Srivastava is doing very interesting work with Riemannian shape spaces and one of its applications is to DTI white matter fibers. In working with anatomical brain data sets, I have found that for successful classification, we need to use a combination of physical features. So although Dr Srivastava's primary interest is in shape spaces, some of our work in the last year has been to define joint manifolds which can be used for a variety of classification tasks--clustering, labeling, atlas building and quantitative analysis for differential diagnosis. These manifolds may be extended to enable joint analysis that uses not just physical features but also scalar functions.

Afternoon tea in London

Lazy afternoons and tea--my two favorite things. And the English have combined these and made it an institution. So naturally when I was in London last week, I stopped by for tea. Sketch is an ultra trendy place in Mayfair--but how does this compare with an English afternoon in Dubai or Paris? Dubai--I was there in April--was most English. I don't know, it might have been the unhappy brown skinned waitstaff in full livery that reminded me of that very English place, the Viceroy's lodge in Fort William!

Florida in August ...

or France? Well, all of France has shut down whereas Florida is just hot, humid and worse than Singapore. I think I'll take Florida.

Now this is a perfect scene.

It's Pléneuf Val-André, Brittany at its best. It's France in the run-up to August. (Our group went there for a retreat in June. Well, I retreated, some others were paying tribute to Machiavelli.)

So why do I prefer Florida? I'll be working with Anuj Srivastava at FSU, This will be my first opportunity to work closely with a professor. And there will be 4 months of this. I'm excited.

I should mention I have a grant from UEB, and if that is not enough, my regular INRIA CORDIS grant is there. One should be grateful even if it is August and Thanksgiving is many months away.