2447 search results for "GIS"

Multivariate probit regression using (direct) maximum likelihood estimators

May 11, 2011
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Multivariate probit regression using (direct) maximum likelihood estimators

Consider a random pair of binary responses, i.e. with taking values 1 or 2. Assume that probability can be function of some covariates . The Gaussian vector latent structureA standard model is based a latent Gaussian structure, i.e. there exi...

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ABC model choice by DIC

May 10, 2011
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ABC model choice by DIC

Yet another paper on ABC model choice was posted on arXiv a few days ago, just prior to the ABC in London meeting that ended in the pub above (most conveniently located next to my B&B!). It is written by Olivier Francois and Guillaume Laval and the approach relies on DIC for running model selection.

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Data Science Toolset discussion at Data Scientist Summit

May 10, 2011
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Heads-up to anyone attending the sold-out Data Science Summit in Las Vegas this week: I'll be there tomorrow and Thursday for the conference and to discuss R on the panel discussion "Data Science Toolset - Recipes That Win" (more details about the panel discussion below.) I'm looking forward to meeting with the other R users there -- tweet or...

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Problems with plyr — the memory/complexity trade-off

May 10, 2011
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Two types of R users My overwhelming impression from UseR 2010 is that, generally speaking, there are 2 types of regular R users -- those who have heard and are made uncomfortable by the idea of the *apply() functions, and those who really get it. In ...

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Extending mtable() to ivreg, gls and robust standard errors

May 9, 2011
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Extending mtable() to ivreg, gls and robust standard errors

I have written several extensions of the mtable() command in the memisc library that may come in handy. The methods are available in a package I have written called tonymisc (now, available on CRAN). A zipped folder with my package files is available...

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Extending mtable() to ivreg, gls and robust standard errors

May 9, 2011
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Extending mtable() to ivreg, gls and robust standard errors

I have written several extensions of the mtable() command in the memisc library that may come in handy. The methods are available in a package I have written called tonymisc (now, available on CRAN). A zipped folder with my package files is available...

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First-Cut Approach to Synchronizing Field Notes with GPS Data

May 9, 2011
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After a week's worth of work in the field, I typically have several pages of hand-written field notes that are associated with GPS waypoints-- badly in need of some kind of transcription/organization. I have yet to find a simple approach for bringing t...

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An Intuitive Approach to ROC Curves (with SAS & R)

May 6, 2011
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An Intuitive Approach to ROC Curves  (with SAS & R)

I developed the following schematic (with annotations) based on supporting documents (link) from the article cited below. The authors used R for their work. The ROC curve in my schematic was output from PROC LOGISTIC in SAS, the scatterplot with m...

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What value is cross country GDP correlation? [Part One]

May 6, 2011
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What value is cross country GDP correlation? [Part One]

The above graph borders on chartjunk (and is nothing like Paul Butler’s amazing Facebook map). We can see some variation in color but mostly it is a set of lines between 152 country capitals with no means to determine which … Continue reading →

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Shell scripting EC2 for fun and profit

May 6, 2011
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Shell scripting EC2 for fun and profit

Lately I’ve been doing some work with creating ad-hoc clusters of EC2 machines. My ultimate goal is to create a simple way to spin up a cluster of EC2 machines for use with Bryan Lewis’s very cool doRedis backend for the R foreach package. But that’s a whole other post. What I was scratching my

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