4480 search results for "git"

(Another) introduction to R

May 27, 2013
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(Another) introduction to R

It’s Memorial Day and my dissertation defense is tomorrow. This week I’m phoning in my blog. I had the opportunity to teach a short course last week that was part of a larger workshop focused on ecosystem restoration. A fellow grad student and I taught a session on Excel and R for basic data analysis.

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Combinatorial optimization with gaoptim package

May 27, 2013
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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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Creating a presence-absence raster from point data

May 27, 2013
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Creating a presence-absence raster from point data

I’m working on generating species distribution models at the moment for a few hundred species. Which means that I’m trying to automate as many steps as possible in R to avoid having to click buttons hundreds of times in ArcView. … Continue reading →

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BISON USGS species occurrence data

May 27, 2013
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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...

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BISON USGS species occurrence data

May 27, 2013
By
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...

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Using R to visualize geo optimization algorithms

May 26, 2013
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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...

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Sentiment analysis finds trouble in the Enron emails

May 24, 2013
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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...

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Compiling R from Source with OpenMP, Accelerate and MKL in OS X

May 24, 2013
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Compiling R from Source in OS X I set out to find out whether I could speed up R by compiling it from source and: using Apple´s Accelerate Framework enabling OpenMP (which is disabled under OS X and Windows by default, but enabled under Linux) using Intel´s Intel´s Math Kernel Library I also wanted to know how an implicit parallel library,...

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Working with shapefiles, projections and world maps in ggplot

May 23, 2013
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Working with shapefiles, projections and world maps in ggplot

In this post I show some different examples of how to work with map projections and how to plot the maps using ggplot. Many maps that are using the default projection are shown in the longlat-format, which is far from optimal. Here I show how to use either the Robinson or Winkel Tripel projection. Read more

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Generating a Markov chain vs. computing the transition matrix

May 23, 2013
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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....

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