The R package dcemriS4 is a collection of functions, with examples and documentation, that allows one to perform voxel-wise quantitative analysis of dynamic contrast-enhanced MRI (DCE-MRI) or diffusion-weighted imaging (DWI) data.  The primary... [Read more...]

The class started yesterday with a small but focussed and responsive audience! Given the background of the students, and in particular their clear proficiency in R!, I switched between the original slides of Introducing Monte Carlo Methods with R and those of my Monte Carlo Statistical Methods: course, updated by ... [Read more...]

Revolution Analytics is growing, and we're looking for some skilled R Hackers to work in our pre-Sales team. A big part of our task is showing companies how R is such a great tool for modern data analysis (especially compared to those older tools with 3- or 4-letter acronyms). So ... [Read more...]

Roll [1984] proposed a model for the bid-ask spread that was based on first-order serial correlation.  His empirical tests were based on daily and weekly frequency equity data, and based on the results he concluded there were informational inefficiencies (or that there was very short term non-stationarity in expected returns).More ... [Read more...]

A few months ago I showed you how to syntax-highlight R code using Github Gists for displaying R code on your blog or other online medium. The idea's really simple if you use blogger - head over to gist.github.com, paste in your R code, create a public "gist", ... [Read more...]

Google Earth Access Trends: Daily Requests read more [Read more...]

By guest blogger Joseph Rickert. I was very happy to be a part of the ACM Data Mining camp held last Saturday (November 13th) at eBay. It was a big day for discussing hot topics in data mining, Mahout, parallel SVMs etc, and also a pretty big day for R. ... [Read more...]

A few weeks ago I wrote about ways to compare major-party returns in US House elections. I experimented with several visualizations, none as useful as the seats-votes curve. A traditional seats-votes cure measures average party performance against individual US House results. Our simplified curve uses a density plot to measure ... [Read more...]

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Feature selection is an important step for practical commercial data mining which is often characterised by data sets with far too many variables for model building. In a previous post we looked at all-relevant feature selection using the Boruta package while in this post we consider the same (artificial, toy) ... [Read more...]

In R, you can use  both ‘=’ and ‘ rm(x) __ mean(x=1:10) [...] [Read more...]

There's an interesting article in the NYT today about the emerging discipline of "digital humanities": extracting digital data from historical archives to answer questions from the Arts and Humanities. From the article: Members of a new generation of digitally savvy humanists argue it is time to stop looking for inspiration ... [Read more...]

Just received this email from José Bernardo about an exciting postdoc position in Wharton: POST-DOCTORAL FELLOW – DEPARTMENT OF STATISTICS, THE WHARTON SCHOOL The Department of Statistics at The Wharton School of the University of Pennsylvania is seeking candidates for a Post-Doctoral Fellowship. This research fellowship provides full funding without any ... [Read more...]

Especially for programmers that come to R from other languages, R sometimes gets dinged about the speed of its for loops. But a lot of the time, where you might have needed an iterative loop in another language to solve a specific task, you don't need a for loop in ... [Read more...]

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Feature selection is an important step for practical commercial data mining which is often characterised by data sets with far too many variables for model building. There are two main approaches to selecting the features (variables) we will use for the analysis: the minimal-optimal feature selection which identifies a small (... [Read more...]

Feature selection is an important step for practical commercial data mining which is often characterised by data sets with far too many variables for model building. There are two main approaches to selecting the features (variables) we will use for the analysis: the minimal-optimal feature selection which identifies a small (... [Read more...]

A few weeks ago, I shared a series of choropleth maps of U.S. presidential election returns, illustrating the relative support for Democratic, Republican, and third Party candidates since 1920. The granularity of these county level results led me to wonder whether it would be possible to develop an isarithmic map ... [Read more...]

As already announced on Statisfaction, I will start a short [14 hour] course in English based on Introducing Monte Carlo Methods with R at ENSAE next Tuesday. The slides were written by George Casella for a course he gave in Italy last spring and he kindly agreed on making them available ... [Read more...]

Tomorrow is the last day to enjoy the first edition of Montpellier's ZAT! (Zones Artistiques Temporaires). I was there this afternoon and tonight, but I found it much more picture worthy tonight: Other people have also taken pictures and sha... [Read more...]