igraph and SNA: an amateur’s dabbling

June 29, 2012
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igraph and SNA: an amateur’s dabbling

I’ve been playing with the igraph package a bit lately (see previous post HERE) and wanted to approach a problem I once visited in the past. The basic gist of the problem is this: Students in a class are asked … Continue reading →

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SYTYCD — where are these terrific dancers come from?

June 29, 2012
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It’s Saturday midnight and I’m already sleepy. However, after several hours, I finally got this google geographic map embedded in my post. Aha!!! This is about 20 finalists from the 9th season of So You Think You Can Dance. I count the states … Continue reading →

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Simple and heuristic optimization

June 29, 2012
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Simple and heuristic optimization

This week, at the Rmetrics conference, there has been an interesting discussion about heuristic optimization. The starting point was simple: in complex optimization problems (here we mean with a lot of local maxima, for instance), we do not necessarily need extremely advanced algorithms that do converge extremly fast, if we cannot ensure that they reach the optimum. Converging extremely fast, with a...

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Wrap-up on Blogging with R Markdown and tumblr

June 29, 2012
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This is a wrap-up post to summarize a few of the issues I’ve found so far with blogging on tumblr with R Markdown. tumblr Puts a 1Mb Cap On Its HTML Editor Fair warning. When I tried eating my own dogfood while writing the previous posts, I found that I had to manually upload all those pretty screenshots of the tumblr interface. For some...

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igraph and structured text exploration

June 29, 2012
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igraph and structured text exploration

I am in the slow process of developing a package to bridge structured text formats (i.e. classroom transcripts)  with the tons of great R packages that visualize and analyze quantitative data (If you care to play with a rough build … Continue reading →

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Trying for a baby? Here’s how long it might take.

June 29, 2012
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Trying for a baby? Here’s how long it might take.

Wanting to start a family the natural way? For a healthy 45-year-old woman, you may be in for a five-year wait. That's the conclusion of Richie Cotton, a UK-based data scientist, who discovered when he and his girlfriend wanted to start a family that statistics on how long it takes to get pregnant are hard to come by. The...

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Horizon Plot Already Available

June 29, 2012
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Horizon Plot Already Available

When I wrote Cubism Horizon Charts in R, I should have known that horizon plot functionality already exists in R http://rgm2.lab.nig.ac.jp/RGM2/func.php?rd_id=latticeExtra:horizonplot and in this case in one of my already favorite packages latticeExtra...

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multiplicitiesoffreedom demonstrates Chaos Theory in Excel. If…

June 29, 2012
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multiplicitiesoffreedom demonstrates Chaos Theory in Excel. If…

multiplicitiesoffreedom demonstrates Chaos Theory in Excel. If he filled in more initial values, you would see a thick bar—like a picture of white-noise. Butterflies flapping their wings in Vermont to change the wind in Hangzhou? A drop of water on ...

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Bayesian credible intervals in the mainstream medical literature

June 29, 2012
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I have sometimes heard complaints from collaborators that it will be impossible to have their work published in the mainstream literature unless a p-value is reported. This post is to report yet another counterexample that was recently published; a meta-analysis for the odds of perioperative bleeding complications in patients taking one of several anticoagulant/antiplatelet drugs.

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Impact of hardware characteristics on detectable fault behavior

June 29, 2012
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Impact of hardware characteristics on detectable fault behavior

Preface. This is the first of what I hope will be many posts analysing experimental data, that will eventually end up in my empirical software engineering with R book (this experiment was chosen because it happens to be the one I am currently working on; having just switched to using Asciidoc I have a backlog

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Decline Effect in Linguistics?

June 29, 2012
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Josef Fruehwald writes: In the past few years, the empirical foundations of the social sciences, especially Psychology, have been coming under increased scrutiny and criticism. For example, there was the New Yorker piece from 2010 called “The Truth Wears Off” about the “decline effect,” or how the effect size of a phenomenon appears to decrease The post Decline...

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The inner workings of R objects

June 29, 2012
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The inner workings of R objects

R is an object oriented language. You provide a name and R supplies that name with various properties. In the simplest case, you can assign a number to a name. This will only have a few attributes, such as its class, length etc: i <- 5 names(i) #NULL class(i) # "integer" attr(i, "name") #NULL dim(i)

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Rcpp 0.9.13

June 29, 2012
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The bug-fix in version 0.9.12 of Rcpp turned out to be incomplete, so a new version 0.9.13 is now on CRAN and will get to Debian shortly. The Rcpp::Enviroment constructor is now properly fixed (using the global environment as a default value). As ...

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Solving mastermind with R

June 29, 2012
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In my last post I have shown a solution to classical sorting problem in R. So I thought that this time it would be nice to generate a strategy for playing Mastermind using R.It was shown by D.E. Knuth that Mastermind code can be bro...

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impacTwit : How big is your work on twitter?

June 29, 2012
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impacTwit : How big is your work on twitter?

There’s a great Tom Waits song from the album “Mule Variations” called “Big in Japan”. The beauty of saying you’re big in Japan is that no one can ever really verify the statement (or at least that was more true in 1999). You might assert “my work is big on twitter”, and hey, how would I know?...

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Use IUCN API with R & XPath

June 28, 2012
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Use IUCN API with R & XPath

Thanks to a posting on R-sig-eco mailing list I learned of the IUCN-API. Here's a simple example for what can be done with it (output as pdf is HERE):require(XML)require(maptools)require(jpeg)input = "panthera-uncia"h <- htmlParse(paste("http://api....

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Big Data Generalized Linear Models with Revolution R Enterprise

June 28, 2012
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Big Data Generalized Linear Models with Revolution R Enterprise

R''s glm function for generalized linear modeling is very powerful and flexible: it supports all of the standard model types (binomial/logistic, Gamma, Poisson, etc.) and in fact you can fit any distribution in the exponential family (with the family argument). But if you want to use it on a data set with millions or rows, and especially with more...

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Preparing Spectrum to import into "ChemoSpec"

June 28, 2012
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Preparing Spectrum to import into "ChemoSpec"

In this video I show I to prepare a spectrum to import later into ChemoSpec:The software I use gives the option to export the spectrum as a TXT file.This file is open with Excel and saved as CSV, to import later with others into ChemoSpec.

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Updating R but keeping your installed packages

June 28, 2012
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This is probably an issue that has been addressed by many blog posts (including these ones: and ), and can be deduced from R Installation and Administration manual. However, I will post it here for future reference. The problem is that w...

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Two tips: adding title for graph with multiple plots; add significance asterix onto a boxplot

June 28, 2012
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Two tips: adding title for graph with multiple plots; add significance asterix onto a boxplot

I've not added tips for a while. Here is it for today:1. How to add title for graph with multiple plots?par(mfrow=c(1,2),oma = c(0, 0, 2, 0))plot(1:10,  main="Plot 1")plot(1:100,  main="Plot 2")mtext("Title for Two Plots", outer = TRUE, cex =...

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When SAP HANA met R – Bring home your graphics

When SAP HANA met R – Bring home your graphics

A couple of days ago, I started to think about SAP HANA and R on Amazon Web Services...as far as I know, graphics can't get generated using this kind of integration because the graphic will get generated on the server and could not make the trip back i...

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Reminder: Next Kölner R User Meeting 6 July 2012

June 27, 2012
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Reminder: Next Kölner R User Meeting 6 July 2012

This post is a quick reminder that the next Cologne R user group meeting is only one week away. We will meet on 6 July 2012. The meeting will kick off at 18:00 with three short talks at the Institute of Sociology and will continue, even more informal, ...

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How do I Create the Identity Matrix in R?

June 27, 2012
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How do I Create the Identity Matrix in R?

I googled for this once upon a time and nothing came up. Hopefully this saves someone ten minutes of digging about in the documentation. You make identity matrices with the keyword diag, and the number of dimensions in parentheses. > diag(3) [,...

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Orbitz and the Macs: Signals, not segmentation

June 27, 2012
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By now you've probably heard about the fact that Orbitz users accessing the site via Macs are seeing more expensive hotel options when they search. But it seems worth clearing up a couple of fallacies. First, it's not as if the same hotel room is being offered at a higher prices to Mac users. (So no, using Windows to...

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Sleep – Part II

June 27, 2012
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Sleep – Part II

Still gettin' it? I'm off to Montreal for Jazzfest.

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PluginR in mods.tiki.org updated

June 27, 2012
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PluginR in mods.tiki.org updated

PluginR has been updated in mods.tiki.org. So what? Do I need to update my PluginR? How can I do it? PluginR resides in a subversion (svn) repository in sourceforge.net. Files can be fetched at any time by anyone using svn (see details in http://de...

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Access data quickly and easily: data.table package

June 27, 2012
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This article gives a brief overview of the data.table package written by M. Dowle, T. Short, S. Lianoglou. A data.table is an extension of a data.frame created to reduce the working time of the user in two ways programming time … Continue reading →

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Effect of sample size on the accuracy of Cohen’s d estimates (95 % CI)

June 27, 2012
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Effect of sample size on the accuracy of Cohen’s d estimates (95 % CI)

When talking about confidence intervals, Jacob Cohen famously said: “I suspect that the main reason they are not reported is that they are so embarrassingly large!” (Cohen, 1994). In this post I'll take a look at the relationship between the 95 % CI for Cohen's d and it's corresponding sample size.

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Solving Big Problems with Oracle R Enterprise, Part II

June 27, 2012
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Solving Big Problems with Oracle R Enterprise, Part II

Part II – Solving Big Problems with Oracle R Enterprise In the first post in this series (see https://blogs.oracle.com/R/entry/solving_big_problems_with_oracle), we showed how you can use R to perform historical rate of return calculations against investment data sourced from a spreadsheet.  We demonstrated the calculations against sample data for a small set of accounts.  While this worked...

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