I’m Hiring!

February 24, 2012
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I direct the Bioinformatics Core at the University of Virginia, and I'm hiring. Visit this link on the UVA Jobs website for more information. Here's the description:The University of Virginia Bioinformatics Core is seeking a full-time position as a bio...

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How to save high frequency data in mongodb

February 24, 2012
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Are you looking for ways how to save real time, high frequency data taken from Interactivebrokers.com API ? I built an example in C++ which saves all incoming data in Mongodb. Check this link if you are interested: https://github.com/kafka399/TwsMongo  

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Synchronous vs. asynchronous agent activation example

February 24, 2012
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Synchronous vs. asynchronous agent activation example

This time I have implemented NetLogo Voting model to verify how agent activation scheme influences the results.The code executing the simulation is given below. It simulates two types of voter preferences encoded as 1 and -1. In this way...

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Analyzing weblog data with R

February 23, 2012
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Analyzing weblog data with R

The R-chart blog explains how to read a weblog file into R, so you can analyze traffic to a website. For example, here's a page request chart created with R: Now, charts like this are stock-in-trade for tools like Google Analytics, but this is still useful if you want to look at the performance of a site that hasn't...

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GSoC Project #2 for 2012

February 23, 2012
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GSoC Project #2 for 2012

In my prior post, I discussed the origins of the first GSoC project I posted this year. The second GSoC project I’ve proposed is around the writing and code of Attilio Meucci, an adjunct professor at Baruch College – CUNY and an excellent speaker (I saw him at the University of Chicago when he spoke

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Large-scale Inference

February 23, 2012
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Large-scale Inference

Large-scale Inference by Brad Efron is the first IMS Monograph in this new series, coordinated by David Cox and published by Cambridge University Press. Since I read this book immediately after Cox’ and Donnelly’s Principles of Applied Statistics, I was thinking of drawing a parallel between the two books. However, while none of them can

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Pocketbook costs of software

February 23, 2012
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Pocketbook costs of software

I have always been provided SAS as part of my job, so I never really realized how much it cost. I’ve bought Stata before, and of course R . I recently found out how much a reasonable bundle of SAS modules along with base SAS costs per year per seat, at least under the GSA.

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Ternary ifelse ( ?: ) in different languages

February 23, 2012
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AWK$ awk 'ORS=NR%3?",":"\n"' student-marksPerl /PHP$result = ($a > $b) ? $x : $y;In Per6, use double ? and ! instead.$result = ($a > $b) ?? $x !! $y;Rifelse(a>0,a,0)Ternary operator (if?true:false)bash/linuxternary operator ? : is ju...

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PCA for NIR Spectra_part 002: "Score planes"

February 23, 2012
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PCA for NIR Spectra_part 002: "Score planes"

The idea of this post is to compare the score plots for the first 3 principal components obtained with the algorithm “svd” with the scores plot of  other chemometric software (Win ISI in this case). Previously I had exported the yarn spectra t...

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Prediction: the Lasso vs. just using the top 10 predictors

February 23, 2012
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Prediction: the Lasso vs. just using the top 10 predictors

One incredibly popular tool for the analysis of high-dimensional data is the lasso. The lasso is commonly used in cases when you have many more predictors than independent samples (the n « p) problem. It is also often used in the context of predictio...

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Visualization in regression analysis

February 23, 2012
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Visualization in regression analysis

Visualization is a key to success in regression analysis. This is one of the (many) reasons I am also suspicious when I read an article with a quantitative (econometric) analysis without any graph. Consider for instance the following dataset, obtai...

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Example 9.21: The birthday "problem" re-examined

February 23, 2012
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Example 9.21: The birthday "problem" re-examined

The so-called birthday paradox or birthday problem is simply the counter-intutitive discovery that the probability of (at least) two people in a group sharing a birthday goes up surprisingly fast as the group size increases. If the group is only 23 peo...

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Gini index and Lorenz curve with R

February 23, 2012
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Gini index and Lorenz curve with R

You can do anything pretty easily with R, for instance, calculate concentration indexes such as the Gini index or display the Lorenz curve (dedicated to my students). Although I did not explain it during my lectures, calculating a Gini index or displaying the Lorenz curve can be done very easily with R. All you have

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Maps with R (III)

February 23, 2012
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Maps with R (III)

In my previous posts (1 and 2) I wrote about maps with complex legends but without any kind of interactivity. …Continuar leyendo »

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another X’idated question

February 23, 2012
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another X’idated question

An X’idated reader of Monte Carlo Statistical Methods had trouble with our Example 3.13, the very one our academic book reviewer disliked so much as to “diverse a 2 star”. The issue is with computing the integral when f is the Student’s t(5) distribution density. In our book, we compare a few importance sampling solutions,

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Visualization in regression analysis

February 23, 2012
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Visualization in regression analysis

Visualization is a key to success in regression analysis. This is one of the (many) reasons I am also suspicious when I read an article with a quantitative (econometric) analysis without any graph. Consider for instance the following dataset, obtained from http://data.worldbank.org/, with, for each country, the GDP per capita (in some common currency) and the infant mortality rate...

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Setting up FastRWeb on Mac OS X

February 23, 2012
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Setting up FastRWeb on Mac OS X

FastRWeb is an infrastructure that allows any webserver to use R scripts for generating dynamic content, such as web pages and graphics. In this post, you’ll learn how to install and set up FastRWeb on a Mac. This tutorial is expendable to any Unix-like operating system. It is an adaptation from Jay Emerson’s post, Setting

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What to do about publishing data?

February 22, 2012
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What to do about publishing data?

There seems to be a scale that’s tipping at the moment: Data or code that should be published* is often not.  This should seem like an odd statement for anyone in science, but it should be easy to show that most publications … Continue reading →

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Introduction to R and Revolution R Enterprise: Slides

February 22, 2012
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If you missed this morning's webinar, Revolution R Enterprise, 100% R and More, I've embedded the slides below. Interestingly, about half of today's participants were SAS users, and the remainder R users. The first section introduces open-source R, and the second describes the additional features of Revolution R Enterprise. View more presentations from Revolution Analytics Unfortunately we had a...

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Diamonds vs. water smackdown in playitbyr-powered podcast

February 22, 2012
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Apparent Reason, my new monthly podcast, is a boisterous and non-technical discussion of economics and statistics. In that format I don't have the luxury of showing charts and graphs to complement my discussion, so I use the playitbyr package to represent the data as sound. (Apparently February is a great month to start R-related podcasts!

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A Sequence Clustering Model in R

February 22, 2012
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A Sequence Clustering Model in R

I’ve just released my first R package! Over the past 1.5 years or so, I’ve been studying an obscure statistical model over ranking (full, or partial) data called Mallows’ model.  It hypothesizes that a set of sequence data has a “modal” sequence about which the data cluster, and that the data fall away from that

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PCA for NIR Spectra_part 001: "Plotting the loadings"

February 22, 2012
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PCA for NIR Spectra_part 001: "Plotting the loadings"

There are different algorithms to calculate the Principal Components (PCs). Kurt Varmuza & Peter Filzmozer explain  them in their book: “Introduction to Multivariate Statistical Analysis in Chemometrics”.I´m going to apply one of them, to...

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The New York Yankees Payroll vs Everyone Else (Major League Baseball)

February 22, 2012
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The New York Yankees Payroll vs Everyone Else (Major League Baseball)

Description: Major League Baseball payrolls for all teams since 1985. The New York Yankees payroll is highlighted with results defined by the shape of the point.Data:http://www.baseball-databank.org/ Analysis: For years fans of Major League Baseball (MLB) have been crying...

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Non overlapping labels on a ggplot scatterplot

February 22, 2012
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Non overlapping labels on a ggplot scatterplot

This is a very quick post just to share a quick tip on how to add non overlapping labels to a scatterplot in ggplot using a great package called directlabels. The trick is to make each point a single member group using an aesthetic like colour and then apply the direct.label function with the first.qp … Continue reading...

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Log File Analysis with R

February 21, 2012
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Log File Analysis with R

 R often comes up in discussions of heavy duty scientific and statistical analysis (and so it should).  However, it is also incredibly handy for a variety of more routine developer activities.   And so I give you… log file analysis with R!  I was just involved in the launch of gradesquare.com (go ahead – click...

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A Heartfelt Thank You and the Resulting GSoC Project

February 21, 2012
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A Heartfelt Thank You and the Resulting GSoC Project

PerformanceAnalytics has long enjoyed contributions from users who would like to see specific functionality included. Diethelm Wuertz at ETHZ, who is the author and sponsor of all the various R/Metrics packages is one of those contributors. I first met Diethelm when he hosted a conference on high-frequency data in the early 1990′s (where we fretted

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Webinar Wednesday: Introduction to Revolution R Enterprise

February 21, 2012
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If you haven't yet had a chance to catch my regularly-scheduled webinar, "Revolution R Enterprise - 100% R and More", it's a quick 30-minute introduction to the R language and the added features of Revolution R Enterprise. It's also a chance to ask me any questions you might have about R or Revolution Analytics during the live broadcast (starts...

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Berkeley Earth Surface Temperature: V1.5

February 21, 2012
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Berkeley Earth Surface Temperature: V1.5

My R package designed to import all of the Berkeley Earth Surface temperature data is officially on CRAN, as BerkeleyEarth.  The version there is 1.3 and I’ve completed some testing with the help of David Vavra. The result of that is version 1.5 which is available here at the drop box. I’ll be posting that

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polar histogram: pretty and useful

February 21, 2012
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polar histogram: pretty and useful

Do you have tens of histograms to show but no room to put them all on the page? As I was reading this paper in Nature Genetics, I came across a simple and clever way of packing all this information … Continue reading →

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