NHANES Data: Management with R

September 9, 2010
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David Winsemius discusses the analysis of the NHANES data set to create models that better predict Hepatitis C infection.

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Harvesting & Analyzing Interaction Data in R: The Case of MyLyn

September 9, 2010
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Sean Goggins presents a network analysis of MyLyn software development project.

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Typo in Chapter 5

September 9, 2010
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Typo in Chapter 5

Gilles Guillot from Technical University of Denmark taught a course based on our R book and he pointed out to me several typos in Chapter 5 of “Introducing Monte Carlo Methods with R”: p.137 second equation from bottom should be p. 138  Example 5.7 denominator in the gradient should be

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The future of R

September 8, 2010
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Some thoughts from Christian, including this bit: We need to consider separately 1. R's brilliant library 2. R's not-so-brilliant language and/or interpreter. I don't know that R's library is so brilliant as all that--if necessary, I don't thi...

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Webinar September 22: Deploying R

September 8, 2010
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In 2 weeks, on Wednesday September 22, I'll be hosting a webinar in conjunction with Andrew Lampitt at Jaspersoft. This new webinar is all about how to Deploy R: in other words, how to use the new server-based capabilities of Revolution R Enterprise 4 for Linux to embed the results of R scripts into applications and web pages. One...

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ECG Project

September 8, 2010
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ECG Project

In an earlier post, I described some ECG signal processing. In fact, these recordings were from my own heart, and I had collected them using a homemade ECG. The following is a repost from my old site describing the device. I assembled an instrumentation amplifier to measure cardiac potentials (i.e. an electrocardiograph (ECG)). The analog-to-digital

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Computer languages and Applied Math

September 8, 2010
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There is no question that computer languages have helped pushed the envelope for applied mathematics.  It is hard to imagine where we would be without airline scheduling, supply chain management, or inventory control if it were not for all of the ...

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Computer languages and Applied Math

September 8, 2010
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There is no question that computer languages have helped pushed the envelope for applied mathematics.  It is hard to imagine where we would be without airline scheduling, supply chain management, or inventory control if it were not for all of the ...

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Clipping a Surface By a Polygon

September 8, 2010
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Clipping a Surface By a Polygon

Background: A common function in standard GIS software enables users to create a raster surface and extract values or clip it based on a set of polygons. This may be used in cases where you want analysis to be constrained to within a town’s boundaries or a coastline. This tutorial will outline how to create

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Canterbury Earthquakes part III

September 8, 2010
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Canterbury Earthquakes part III

As more people keep following the GeoNet website, they are starting to notice the seismic activity in areas other than Christchurch. A few people I've talked to have expressed concern that the Saturday 7-pointer has sparked earthquakes around the count...

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Canterbury Earthquakes part III

September 8, 2010
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Canterbury Earthquakes part III

As more people keep following the GeoNet website, they are starting to notice the seismic activity in areas other than Christchurch. A few people I've talked to have expressed concern that the Saturday 7-pointer has sparked earthquakes around the count...

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Julien on R shortcomings

September 8, 2010
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Julien on R shortcomings

Julien Cornebise posted a rather detailed set of comments (from Jasper!) that I thought was interesting and thought-provoking enough (!) to promote to a guest post. Here it is , then, to keep the debate rolling (with my only censoring being the removal of smileys!). (Please keep in mind that I do not endorse everything

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Straight, curly, or compiled?

September 7, 2010
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Christian Robert, whose blog I commented-on here once before, had followed up on a recent set of posts by Radford Neal which had appeared both on Radford's blog and on the r-devel mailing list. Now, let me prefix this by saying that I really enjoyed Radford's posts. He obviously put a lot of time into finding a number of (all...

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Straight, curly, or compiled?

September 7, 2010
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Christian Robert, whose blog I commented-on here once before, had followed up on a recent set of posts by Radford Neal which had appeared both on Radford's blog and on the r-devel mailing list. Now, let me prefix this by saying that I really enjoyed R...

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Straight, curly, or compiled?

September 7, 2010
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Christian Robert, whose blog I commented-on here once before, had followed up on a recent set of posts by Radford Neal which had appeared both on Radford's blog and on the r-devel mailing list. Now, let me prefix this by saying that I really enjoyed Radford's posts. He obviously put a lot of time into finding a number of (all...

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Ah Bach…

September 7, 2010
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Ah Bach…

As announced by David Smith over at Revolution Analytics,  a ggplot2 Case Study Competition is on...   Rather than blogging for the last few days, I cobbled together an entry.  It is not a particularly mind bending use of ...

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Ah Bach…

September 7, 2010
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Ah Bach…

As announced by David Smith over at Revolution Analytics,  a ggplot2 Case Study Competition is on...   Rather than blogging for the last few days, I cobbled together an entry.  It is not a particularly mind bending use of ...

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Eigenimages: The AT&T Cambridge Faces Database

September 7, 2010
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Eigenimages: The AT&T Cambridge Faces Database

I picked up the AT&T Laboratories Cambridge database of faces for a clustering application. The database consists of images of 40 distinct subjects, each in 10 different facial positions and expressions. Typically, the goal of clustering in these data is to recover the ‘true’ partition, or that which isolates images of distinct subjects. Each image

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Revolution R Enterprise 4.0 free download for academics

September 7, 2010
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The Windows version of our latest enterprise distribution of R, Revolution R Enterprise 4.0, is now being delivered to subscribers and is also available for free download for members of the academic community. Revolution R Enterprise 4.0 is a major update, and includes many new and improved features: Based on R 2.11.1, the current release of the R. See...

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Barchart or Dotchart?

September 7, 2010
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Barchart or Dotchart?

Which of the following two charts (both created with R) to you prefer? This dotchart: Or this bar chart? Andrew Gelman (who, incidentally, is speaking at the October NYC UseR meeting) prefers the dotchart prefers a line plot (update: see Gelman's comment, below), but personally I think the bar chart is more easily interpreted. What do you think? You...

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Example 8.4: Including subsetting conditions in output

September 7, 2010
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Example 8.4: Including subsetting conditions in output

A number of analyses perform operations on subsets. Making it clear what observations have been excluded or included is helpful to include in the output.SASThe where statement (section A.6.3) is a powerful and useful tool for subsetting on the fly. (...

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Embed R Code with Syntax Highlighting on your Blog

September 7, 2010
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If you use blogger or even wordpress you've probably found that it's complicated to post code snippets with spacing preserved and syntax highlighting (especially for R code). I've discovered a few workarounds that involve hacking the blogger HTML templ...

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Writing a Spatial Function: The Location Quotient

September 7, 2010
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Writing a Spatial Function: The Location Quotient

Background: In some cases it is necessary to conduct the same analysis multiple times on either the same or different data. In such circumstances it is worth writing a function to simplify the code. In this example the location quotient provides a simple calculation easily written in to a function. The location quotient (LQ) is

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Canterbury Earthquakes part II

September 7, 2010
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Canterbury Earthquakes part II

Since posting last night, there's been several more aftershocks, including several big ones. The total now stands (at 7:00pm) at 304 aftershocks, 70 greater than 4 on the Richter scale, 29 greater than 4.5, and 10 greater than 5. A couple of the fives ...

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Canterbury Earthquakes part II

September 7, 2010
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Canterbury Earthquakes part II

Since posting last night, there's been several more aftershocks, including several big ones. The total now stands (at 7:00pm) at 304 aftershocks, 70 greater than 4 on the Richter scale, 29 greater than 4.5, and 10 greater than 5. A couple of the fives ...

Read more »

Confidence Bands for Universal Scalability Models

September 7, 2010
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Confidence Bands for Universal Scalability Models

In the recent GDAT class, confidence intervals (CI) for performance data were discussed. Their generalization to confidence bands (CB) for scalability projections using the USL model also came up informally. I showed a prototype plot but it was an ugly hack. Later requests from GDAT attendees to apply CBs to their own data meant I had...

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Confidence Bands for Universal Scalability Models

September 7, 2010
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Confidence Bands for Universal Scalability Models

In the recent GDAT class, confidence intervals (CI) for performance data were discussed. Their generalization to confidence bands (CB) for scalability projections using the USL model also came up informally. I showed a prototype plot but it was an ugly hack. Later requests from GDAT attendees to apply CBs to their own data meant I had...

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CCE

September 7, 2010
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CCE

Wasnt that hard. green is land, blue is sea. new data awaits you. old data taken down For Zeke: Green is landcoast cells, blue is seacoast.  The cells are AREA weighted per cce request but not Fractiionally weighted. That is if a cell is 90% land and 10% water, this weighting is NOT applied. I

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Truly random?!

September 6, 2010
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Truly random?!

Having purchased the September edition of La Recherche because of its (disappointing!) coverage on black matter, I came by a short coverage on an Intel circuit producing “truly random” numbers… I already discussed this issue in an earlier post, namely that there is no reason physical generators are “more” random than congruential pseudo-random generators, but

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