Quite some time ago now, I wrote this function to read some *.gef files into R. "gef" stands for Geotechnical Exchange Format. Details on this data format can be found at http://www.geffiles.nl/, as well as several software tools. I had a long list of ... [Read more...]

The international R User Conference useR! 2012 will be held June 12-15 at Vanderbilt University in Nashville, Tennessee, USA, with a pre-conference full-day course offered on [Read more...]

The K-means algorithm is a method to automatically cluster similar data examples together. The intuition behind K-means is an iterative procedure that starts by guessing the initial centroids, and then refines this guess by repeatedly assigning examples to their closest centroids and then recomputing the centroids based on the assignments. ... [Read more...]

This blog has lasted a whole year already.  Thanks for reading and commenting. There are a couple of announcements: Less blogging: I hope to put in many more years blogging here, but in full disclosure I am blogging for Journal of Ecology now, ... [Read more...]

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Data files on 407 banks, between the dates of 2007 to 2009, on the daily borrowing with the US Federal Reserve bank. The data sets are available from Bloomberg at this address data This is an unprecedented look into the day-to-day transactions of ... [Read more...]

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Revolution Analytics CEO Norman Nie sat down with Cassimir Medford from Business Agility to talk about the problems business today face with respect to Big Data. The two big problems identified: finding adequately trained personnel and locating the right tools. Norman traces the problem of finding skilled practitioners to work ... [Read more...]

This post will conclude the portfolio optimization series.  In this post, we will construct a trading strategy based on portfolio optimization and test the results against the CAPM market portfolio as well as another strategy.It is worth reiterati... [Read more...]

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This is just a quick note to wish you and your family a very healthy and happy holidays and wonderful New Year! I hope you enjoyed reading my blog and thank you for your comments and emails. Here is a short R code that implements an interesting idea from the ... [Read more...]

Version 1.0 of AQP is nearly ready-- after nearly 3 years of development, 2 years on R-Forge, and 1+ year on CRAN. Just pushed version 0.9-9 to R-Forge, and it should be on CRAN within a couple days. Recent changes are listed below, clipped from the NE... [Read more...]

Peter Dalgaard announced today the release of the new R version 2.14.1.  Bellow is the announcement.  For R users who are using windows, I suggest to also have a look at [Read more...]

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A new release 0.9.8 of Rcpp is now on CRAN and will also get into Debian shortly (once I finish building R 2.14.1). This release contains a few incremental changes. Romain, sponsored by by the Open Source Programs Office at Google, had released a... [Read more...]

Those of you following my occasional updates here know that I have previously posted code for graphing Twitter friend/follower networks using R (post #1. post #2). Kai Heinrich was kind enough to send me some updated code for doing so using a newer version of the extremely useful twitteR package. His ... [Read more...]

About a month ago I was discussing the approach that I would like to see in introductory Bayesian statistics books. In that post I mentioned a PDF copy of Doing Bayesian Data Analysis by John K. Kruschke and that I … Continue reading → [Read more...]

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As mentioned in this post, I have been using the powerful combination of the Beautiful Soup and Mechanize modules in Python to build a web scrapers. The amount of data on the web is amazing, and I believe that any quantitatively oriented social scienti... [Read more...]