Monthly Archives: August 2013

Multi-threaded OpenBLAS backported to recent Ubuntu releases

August 13, 2013
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OpenBLAS is a multi-threaded BLAS library that has been available in Ubuntu for a while, minus the multi-threading. This has been fixed for the OpenBLAS package to be released in Saucy Salamander, and I have backported the package to the more recent r...

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The Brand as Affordance: Item Response Modeling of Brand Perceptions

August 13, 2013
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The Brand as Affordance: Item Response Modeling of Brand Perceptions

It is just too easy to think of a brand as a web of associations.  What comes to mind when I say "Subway Sandwich"?  Did you remember a commercial or the "eat fresh" tagline?  Without much effort, one can generate a long list of associat...

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Visualizing Katrina’s strongest winds, with R

August 13, 2013
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Visualizing Katrina’s strongest winds, with R

Here's a new picture of the devastation wrought by Katrina in 2005. This image shows the maximum wind speeds of the hurricane, not at any particular point of time, but over the duration of the entire storm: The data come from NOAA's H*Wind project, which makes windspeed data from sensors on the ground and floating in the ocean available...

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Temporal visualization of records of IndianMoths project using bdvis

August 13, 2013
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Temporal visualization of records of IndianMoths project using bdvis

I was looking for some data set which has some bias in terms of temporal data. I thought of checking out the data from iNaturalist project IndianMoths. This project is aimed at documenting moths from India. This project was initiated in July 2012 but really caught steam in January 2013, with members contributing regularly, minimum

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Temporal visualization of records of IndianMoths project using bdvis

August 13, 2013
By
Temporal visualization of records of IndianMoths project using bdvis

I was looking for some data set which has some bias in terms of temporal data. I thought of checking out the data from iNaturalist project IndianMoths. This project is aimed at documenting moths from India. This project was initiated in July 2012 but really caught steam in January 2013, with members contributing regularly, minimum

Read more »

Stocks and Bonds Behavior by Decade

August 13, 2013
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Stocks and Bonds Behavior by Decade

I struggled with whether or not I should even post this.  It is raw and ugly, but it might help somebody out there.   I might use this as a basis for some more gridSVG posts, but I do not think I have the motivation to finish the analysi...

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Classi-Compare of Raster Satellite Images – Before and After

August 13, 2013
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For my research on the effect of power outages on fertility , we study a period of extensive power rationing that lasted for almost a whole year and affected most of Latin America, but in particular, it affected Colombia. The key difficult was to determine which areas were exposed to the power-outage and the extent to

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Finding Correlations in Data with Uncertainty: Classical Solution

August 13, 2013
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Following up on my previous post as a result of an excellent suggestion from Andrej Spiess. The data are indeed very heteroscedastic! Andrej suggested that an alternative way to attack this problem would be to use weighted correlation with weights being the inverse of the measurement variance. Let’s look at the synthetic data first. This is

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When Discussing Confidence Level With Others…

August 13, 2013
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When Discussing Confidence Level With Others…

This post spawned from a discussion I had the other day. Confidence intervals are notoriously a difficult topic for those unfamiliar with statistics. I can’t really think of another statistical topic that is so widely published in newspaper articles, television, and elsewhere that so few people really understand. It’s been this way since the moment

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Genetic drift simulation

August 13, 2013
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Genetic drift simulation

While preparing for the new teaching semester I have created an implementation of NetLogo GenDrift P local in GNU R.The model works as follows. Initially a square grid having side size is randomly populated with n types of agen...

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