CloudStat School – The Introduction

January 1, 2012
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CloudStat School is a not yet released open source project. The objective is to create an interactive R Learning Platform. The best way to learn R programming is doing while learning. In CloudStat School, you will see a console box at your top left han...

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Reproducible Research with R: Cost of energy and mutual shadows in a two-axis tracking PV system

January 1, 2012
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Reproducible Research with R: Cost of energy and mutual shadows in a two-axis tracking PV system

  Some days ago the journal Renewable Energy published my last paper “Cost of energy and mutual shadows in a …Continuar leyendo »

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Decoding a Substitution Cipher using Simulated Annealing

January 1, 2012
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Decoding a Substitution Cipher using Simulated Annealing

My last post discussed a method to decode a substitution cipher using a Metropolis-Hastings algorithm. It was brought to my attention that this code could be improved by using Simulated Annealing methods to jump around the sample space and avoid some of the local maxima. Here is a basic description of the difference: In a

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R-Function to Source all Functions from a GitHub Repository

January 1, 2012
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R-Function to Source all Functions from a GitHub Repository

Here's a function that sources all scripts from an arbitrary github-repository. At the moment the function downloads the whole repo and sources functions kept in a folder named "Functions" - this may be adapted for everyones own purpose.# Script name: ...

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NIPALS: Principal Components Analysis with "R" (Part: 002)

January 1, 2012
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NIPALS: Principal Components Analysis with "R" (Part: 002)

We started some posts based on the tutorials of:"Multivariate Statistical Analysis using the R package chemometrics"The first post was:Principal Components Analysis with "R" (Part: 001)Now we continue with a second part.The graphics help us to dec...

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Top 20 R posts of 2011 (and some R-bloggers statistics)

January 1, 2012
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Top 20 R posts of 2011 (and some R-bloggers statistics)

R-bloggers.com is now two years young. The site is an (unofficial) online R journal written by bloggers who agreed to contribute their R articles to the site. In this post I wish to celebrate R-bloggers’ second birthmounth by sharing with you: Links to the top 20 posts of 2011 Statistics on “how well” R-bloggers did Read more...

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Monetary Policy & Credit Easing pt. 7: R Econometrics Tests

January 1, 2012
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In post 6 we introduced some econometrics code that will help those working with time-series to gain asymptoticly efficient results.  In this post we look at the different commands and libraries necessary for testing our assumptions and such. Testing our Assumptions and Meeting the Gauss-Markov TheoremIn this section we will seek to test and verify the assumptions of the simple linear...

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Free Online Stanford Machine Learning Course: Andrew Ng. Post Mortem.

January 1, 2012
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Free Online Stanford Machine Learning Course: Andrew Ng. Post Mortem.

Happy New Year to all the viewers of this blog and just a short reminder that the course will be available again this January.http://www.ml-class.org/course/auth/welcomeHaving audited the course, I would highly recommend it to anyone who is interested ...

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RTextTools v1.3.5: Saving models, text labels, and a game plan for 2012

RTextTools v1.3.5 addresses some key concerns that have been raised in recent months. Many of the algorithms used in RTextTools require that any new data presented to a trained classifier contain the same features as the original document-term matrix. Since this rarely (if ever) happens in the real world, I have added an originalMatrix parameter to the create_matrix() function...

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New Year Resolutions

January 1, 2012
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Well, here we go again! It's time of year that we make all of those resolutions - the ones that usually get broken before the holiday decorations have been packed away. Not this year, though!In 2012, and in no particular order, I firmly resolve to:Increase my use of the R statistical environment in my research and teaching, and foster "Reconometrics".Become more...

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Best One-Sentence Pitch for CloudStat (TechCrunch)

December 31, 2011
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Best One-Sentence Pitch for CloudStat (TechCrunch): Techcrunch.com is running a one sentence pitch competition for startup. So, I made one for CloudStat (using their format): My company, CloudStat is developing a cloud-based statistical platform to h...

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Uncertainty in markov chains: fun with snakes and ladders

December 31, 2011
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Uncertainty in markov chains: fun with snakes and ladders

I love board games. Over the holidays, I came across this interesting post over at Arthur Charpentier’s Freakonometrics blog about the classic game of snakes and ladders. The post is a nice little demonstration of how the game can be formulated completely as a Markov chain, and can be analysed simply using the mathematics of

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Color map of Poland for the New Year

December 31, 2011
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Color map of Poland for the New Year

To celebrate the New Year I decided to plot map of Poland in our national colors.It was not so difficult using maps  package. Here is the result:and the code I used to generate it:library(maps)x.mid <- function(x1, x2, y1, y2, y.mid) {&nbs...

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Interview with Kai Chew, CloudStat

December 31, 2011
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Here is an interview with Kai Chew, Founder of Cloudstat. CloudStat is developing a cloud-based statistical platform to help researchers who want to make sense of data to do statistical analysis collaboratively with its high performance computing infra...

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BIG Data

December 31, 2011
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"Big Data" = data that come in amounts that are too large for current computer hardware and software to deal with. That sounds like fun!Norman Nie developed the well known SPSS statistical package in the 1960, and is currently President and CEO of Revolution Analytics, a California company that promotes the use of the R computing...

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Using factor analysis or principal components analysis or measurement-error models for biological measurements in archaeology?

December 31, 2011
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Greg Campbell writes: I am a Canadian archaeologist (BSc in Chemistry) researching the past human use of European Atlantic shellfish. After two decades of practice I am finally getting a MA in archaeology at Reading. I am seeing if the habitat or size of harvested mussels (Mytilus edulis) can be reconstructed from measurements of the The post Using...

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Is R turning into an operating system?

December 31, 2011
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Is R turning into an operating system?

Over the years I convinced my colleagues and IT guys that R and LaTeX/XeLaTeX is the way forward to produce lots of customer reports with individual data, charts, analysis and text. Success!But of course the operating system in the office is still MS W...

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Say Hi to CloudStat!

December 30, 2011
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Hello and welcome to the CloudStat official blog! We’ll be using this space to talk about product updates, getting the most out of CloudStat, and random thoughts on data analysis learning, especially in R language. More about CloudStat can be vie...

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Initial impressions of RangeLab

December 30, 2011
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Initial impressions of RangeLab

I was rummaging around in the source of R looking for trouble, as one does, when I came across what I believed to be a less than optimally accurate floating-point algorithm (function R_pos_di in src/main/arithemtic.c). Analyzing the accuracy of floating-point code is notoriously difficult and those having the required skills tend to concentrate their efforts

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MuroBBS Programming Challenge 1

December 30, 2011
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MuroBBS Programming Challenge 1

It’s been a while since the last post. I started my studies as a statistics major in university and have been doing little with R but mostly just reading other blogs and taking our university’s R course which was just … Continue reading →

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Monetary Policy and Credit Easing pt. 6: Empirical Estimation and Methodology

December 30, 2011
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Monetary Policy and Credit Easing pt. 6: Empirical Estimation and Methodology

IT is now appropriate to lay out our two regression models in full for empirical estimation over our two separate time periods. The first estimation is from 4/1/71 to 7/1/97 and the second is from 4/1/01 to 4/1/11. The methodology employed in the estimation of these two models is a procedure using Generalized Least Squares with a Cochrane-Orcutt, style iterated...

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Over on F1DataJunkie, 2011 Season Review Doodles…

December 30, 2011
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Over on F1DataJunkie, 2011 Season Review Doodles…

Things have been a little quiet, post wise here, of late, in part because of the holiday season… but I have been posting notes on a couple of charts in progress over on the F1DataJunkie blog. Here are links to the posts in chronological order – they capture the evolution of the chart design(s) to

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RcppExamples 0.1.3

December 30, 2011
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A minor new release of the RcppExamples package is now on CRAN. RcppExamples contains a few illustrations of how to use Rcpp. It grew out of documentation for the classic API (now in its own package RcppClassic), and while we added a few more funct...

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You’ve got the whole world in your portfolio

December 29, 2011
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You’ve got the whole world in your portfolio

A famous finance professor once told us that good diversification meant holding everything in the world. Fine, but in what proportion? Suppose you could invest in every country in the world. How much would you invest in each? In a market-capitalization weighted index, you'd invest in each country in proportion to the market value of its investments (its "market capitalization")....

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Benchmarking time series models

December 29, 2011
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Benchmarking time series models

This is a quick post on the importance of benchmarking time-series forecasts.  First we need to reload the functions from my last few posts on times-series cross-validation.  (I copied the relevant code at the bottom of this post so you don't...

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dcemriS4 0.46

December 29, 2011
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dcemriS4 0.46

The R package dcemriS4 provides routines for the quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), along with quantification of diffusion-weighted MRI (ADC = apparent diffusion coefficient) and quantitative T2 map...

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Weecology can has new mammal dataset

December 29, 2011
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Weecology can has new mammal dataset

So the Weecology folks have published a large dataset on mammal communities in a data paper in Ecology.  I know nothing about mammal communities, but that doesn't mean one can't play with the data...Their dataset consists of five csv files: &...

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Weecology can has new mammal dataset

December 29, 2011
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Weecology can has new mammal dataset

So the Weecology folks have published a large dataset on mammal communities in a data paper in Ecology.  I know nothing about mammal communities, but that doesn't mean one can't play with the data... Their dataset consists of five csv fil...

Read more »

Weecology can has new mammal dataset

December 29, 2011
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Weecology can has new mammal dataset

So the Weecology folks have published a large dataset on mammal communities in a data paper in Ecology.  I know nothing about mammal communities, but that doesn't mean one can't play with the data... Their dataset consists of five csv fil...

Read more »