2094 search results for "twitter"

Statistical podcast: Random and Pseudorandom

January 14, 2011
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Statistical podcast: Random and Pseudorandom

This morning when I downloaded the latest version of In our time, I was pleased to see that this weeks topic was “Random and Peudorandom.” If you’re not familiar with “In our time”, then I can I definitely recommend the series. Each week three academics and Melvyn Bragg discuss a particular topic from history, science,

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Remove all rows of an R dataframe

January 13, 2011
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Remove all rows of an R dataframe

I should have probably figured this out a long time ago, but as I get deeper into programming with R, I am finding the need to remove all rows from a dataframe.  I was making this alot harder than it had to be. your.df<- your.df Replace your.df with, your dataframe and you are good

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Survival paper (update)

January 13, 2011
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Survival paper (update)

In a recent post, I discussed some  statistical consultancy I was involved with. I was quite proud of the nice ggplot2 graphics I had created. The graphs nicely summarised the main points of the paper: I’ve just had the proofs from the journal, and next to the graphs there is the following note: It is

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CosmoPMC released

January 12, 2011
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CosmoPMC released

Martin Kilbinger, an astronomer (cosmologist) with whom we had worked on population Monte Carlo for cosmological inference , has made the PMC C codes available on the CosmoPMC webpage. He has also written a CosmoPMC manual that is now available from arXiv. And he very kindly associated me to

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Initial Work on a Post Not Yet Completed

January 12, 2011
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Initial Work on a Post Not Yet Completed

It’s no secret I have been learning R for some time now, and one of the best resources out there is the hashtag rstats on twitter (#rstats).  There is a tremendous community of active users who are always willing to help, but not to mention, you can get a first hand view of some of

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Random variable generation (Pt 3 of 3)

January 12, 2011
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Random variable generation (Pt 3 of 3)

Ratio-of-uniforms This post is based on chapter 1.4.3 of Advanced Markov Chain Monte Carlo.  Previous posts on this book can be found via the  AMCMC tag. The ratio-of-uniforms was initially developed by Kinderman and Monahan (1977) and can be used for generating random numbers from many standard distributions. Essentially we transform the random variable of

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Two short Bayesian courses in South’pton

January 12, 2011
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Two short Bayesian courses in South’pton

An announcement for two short-courses on Introduction to  Bayesian Analysis and MCMC, and Hierarchical Modelling of Spatial and Temporal Data by Alan Gelfand (Duke University, USA) and Sujit Sahu (University of Southampton, UK), are to take place in Southampton on June 7-10, this year. Course 1: Introduction to Bayesian Analysis and MCMC. Date: June 7,

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Introducing the Lowry Plot

January 11, 2011
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Introducing the Lowry Plot

Here at the Health and Safety Laboratory* we’re big fans of physiologically-based pharmacokinetic (PBPK) models (say that 10 times fast) for predicting concentrations of chemicals around your body based upon an exposure. These models take the form of a big system of ODEs. Because they contain many equations and consequently many parameters (masses of organs

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Le Monde puzzle [1]

January 10, 2011
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Le Monde puzzle [1]

Following the presentation of the first Le Monde puzzle of the year, I tried a simulated annealing solution on an early morning in my hotel room. Here is the R code, which is unfortunately too rudimentary and too slow to be able to tackle n=1000. #minimise \sum_{i=1}^I x_i #for 1\le x_i\le 2n+1, 1\e i\le I

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Abusing Amazon’s Elastic MapReduce Hadoop service… easily, from R

January 10, 2011
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Abusing Amazon’s Elastic MapReduce Hadoop service… easily, from R

JD Long's experimental segue package makes it easy to use Amazon's Elastic MapReduce service to fire up a Hadoop cluster and use it for non-Big Data, computationally-intensive tasks. The package provides a cluster-aware version of lapply() which "just works".

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