Wednesday, April 10, 2013

Postdoctoral Position Available

We have a postdoctoral position available on high dimensional analysis of phylogenetics data.  This position is available through the Center for Computational and Molecular Biology at Brown University in Providence, Rhode Island.

The successful candidate will collaborate with Casey Dunn (http://dunnlab.org) from the Department of Ecology and Evolutionary Biology, and Jean Wu (http://www.stat.brown.edu/zwu/) and Rossi Luo (http://sites.google.com/site/xirossiluo/) from the Department of Biostatistics.

Research will focus on extending the ideas presented in the arXiv paper
http://arxiv.org/abs/1302.2978

Funding is available for one year, with the possibility of additional funding for subsequent years. The position is available immediately.

Thursday, April 26, 2012

What Causes Brain to Think?

Brain causes us to behave as who we are, but what causes brain to think (activate)?  Indirect measures of brain activities are usually preferred, such as fMRI, but the resulting statistics usually cannot resolve the causality issue.  The simple box plots (image below, left) show no significant differences of the brain activity under two experimental conditions.  Without modeling what the indirect response function looks like (e.g. HRF), our paper (to appear in Journal of the American Statistical Association) provides a way to resolve the causality question: what causes brain to think?(image below, right)
This method is specifically designed to provide causal interpretation under interference, and is robust against any shape of the response function.  The R package is CIN.

Monday, April 23, 2012

New R Package SCIO Posted

As promised, the new R package for SCIO (and post) has been uploaded to CRAN.  It will be publicly available across all platforms in a few days.

This is a version with the minimal set of functions for estimation.  I will add more functionalities in future releases.

I have also updated our R package clime.  Thanks useRs for all the suggestions.  The JASA paper is here, and the preprint is here.  I have also posted the cancer result using this method on this post.

Friday, March 23, 2012

Statisticians Compute Fast

Fast computation is increasingly important in analyzing data as we are living in an information explosion era.  Here is another paper we submitted and the preprint is on arXiv 1203:3896.  An example in the paper is to compute the brain networks of ADHD children and controls.  Here is a snap shot of the computation time.
The new method is called SCIO.  Will post the R package on CRAN.

Tuesday, March 20, 2012

Genetic Profiling for Breast Cancer Treatment

Our paper, CLIME, appeared in Journal of the American Statistical Association last year.  It is always amazing to me that how science can help shape the future.  Part of the paper employed a mathematical model to study if we can predict the outcome of a breast cancer patient based on her genetic profile.  The prediction performance is interestingly good.
Average (SD) performance of classifying breast cancer treatment outcomes over 100 out-of-sample runs.
Both the sensitivity and specificity are high (>=75%).  The R package for the CLIME method is here on CRAN, and I will provide an update very soon.

Sunday, November 20, 2011

New tools for investment portfolios?

I posted a paper (arXiv: 1111.1133) quite a long time ago on "High Dimensional Low Rank and Sparse Covariance Matrix Estimation via Convex Minimization".  The software for this methodology, LOREC, is here on CRAN.

I still remember the stock market crash in 2009.  This method is used to construct minimal risk stock portfolios.  Here are the variances of monthly returns with different investment goals.
This new method, LOREC, performs favorably comparing with existing methods.  Wish I had found this earlier in 2009.