My recent update of gaoptim package brings up a new function, GAPerm, which can be used to perform combinatorial optimization using the Genetic Algorithm approach. The example below solves a TSP instance with 10 points around a circumference, the...
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BISON USGS species occurrence data
The USGS recently released a way to search for and get species occurrence records for the USA. The service is called BISON (Biodiversity Information Serving Our Nation). The service has a web interface for human interaction in a browser, and two APIs (application programming interface) to allow machines to interact with their database. One of the...
Using R to visualize geo optimization algorithms
Site optimization is the process of finding an optimal location for a plant or a warehouse to minimize transportation costs and duration. A simple model only consists of one good and no restrictions regarding transportation capacities or delivery time. The optimizing algorithms are often hard to understand. Fortunately, R is a great tool to make them more comprehensible.
The basic...
Sentiment analysis finds trouble in the Enron emails
The Enron email dataset, collected during the FERC investigation of the Enron financial scandal, represents the largest publicly available set of emails. This makes theman ideal testbed for sentiment analysis algorithms. Ikanow's Andrew Strite used the open-source Infinit.e framework and a Hadoop cluster to generate sentiment scores for all of the Enron emails, and then used R to manipulate...
Generating a Markov chain vs. computing the transition matrix
A couple of days ago, we had a quick chat on Karl Broman‘s blog, about snakes and ladders (see http://kbroman.wordpress.com/…) with Karl and Corey (see http://bayesianbiologist.com/….), and the use of Markov Chain. I do believe that this application is truly awesome: the example is understandable by anyone, and computations (almost any kind, from what we’ve tried) are easy to perform....
The R-Podcast Episode 13: Interview with Yihui Xie
It’s an episode of firsts on the R-Podcast! In this episode recorded on location I had the honor and privilege of interviewing Yihui Xie, author of many innovative packages such as knitr and animation. Some of the topics we discussed include: Yihui’s motivation for creating knitr and some key new features How markdown plays a
How Important is Variable Selection?
Very. If you have 10 possible independent regressors, and none of which matter, you have a good chance to find at least one is important. A good chance being 40%: prob(one or more looks important) = 1 – prob(non looks … Continue reading →
What happened to six million voters?
The recent elections in Pakistan on May 11 were a great success by all means. In spite of the threats for violence by Al-Qaeda and its local franchises in Pakistan against those who would vote, millions of Pakistanis indeed stepped out to vote for an elected government. The Election Commission of Pakistan (ECP) claimed a voter turnout of 60%....
Video: R, ProjectTemplate, RStudio and GitHub: Automate the boring bits and get on with the fun stuff
This post shares the video from the talk presented on 15th May 2013 by Dr Kendra Vant on ProjectTemplate, github and Rstudio at Melbourne R Users. Overview: Want to minimise the drudge work of data prep? Get started with test … Continue reading →
R 3.0.1 is released
R 3.0.1 (codename “Good Sport”) was released last week. As mentioned earlier by David, this version improves serialization performance with big objects, improves reliability for parallel programming and fixes a few minor bugs. Upgrading to R 3.0.1 You can download …
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
