I was reading an article from Datamation on 70 Open Source Replacements for Small Business when I noticed a glaring omission. Where are the software applications for Operations Research and Analytics? So here is my best addendum to this art...

A link on R-bloggers signaled a series of blogs and videos by IBM Netezza about Thomas Bayes and the consequences of his theorem. Which made me realise this was indeed the 250th anniversary of his death, and that maybe we (as a collective, incl. ISBA) should have done something on April 17th… Before the Revolution

It's great to see new local R user groups popping up around the world, and the latest one is based in Gießen, Germany (about 70km north of Frankfurt). The Giessen R Users Group has its first meeting on May 10 with a discussion on applications of R to social media (with an example related to Twitter). meetup.com: Giessen R...

I can tolerate a lot of things, like the haters on reddit, even a colleague calling me out to be a jerk. But when my wife starts talking to me really fast and using herhands, then I need to rethink my position: Me: “Hey come here and look at these co...

I have been really interested in the "meme" that the Egyptian revolution was "the first social media revolution" and have tolerated infographics that correlate specific twitter activity with events in Egypt beyond. And I am sure we have all reminded ourselves that correlation is not causation. I was recently listening to an Egyptian colleague who

I have been really interested in the "meme" that the Egyptian revolution was "the first social media revolution" and have tolerated infographics that correlate specific twitter activity with events in Egypt beyond. And I ...

Last week I decided to start a weekly column detailing an interesting function each Friday, entirely forgetting that I would be on holiday, without internet access (shock horror!), tomorrow. So here’s your column a little early. The alarm function is something of a novelty, in that all it does is to make an annoying noise

I suffer a little from the age-old affliction of contrarianism. If a software package is used by the majority of the population, I assume it is flawed, highly limited, and its continued use will ultimately result in the downfall of the human race. Conversely, I am always extremely interested in a piece of software that has spread no further...

I suffer a little from the age-old affliction of contrarianism. If a software package is used by the majority of the population, I assume it is flawed, highly limited, and its continued use will ultimately result in the downfall of the human race. Conversely, I am always extremely interested in a piece of software that has spread no further...

I notice that the latest version of R has upped the maximum length of variable names from 256 characters to a whopping 10 000! (See ?name.) It makes the 63 character limit in MATLAB look rather pitiful by comparison. Come on MathWorks! Let’s have the ability to be stupidly verbose in our variable naming! Tagged:

I recently came across a rather interesting investment blog, Timely Portfolio. I have a certain soft spot for that sort of thing, because using my data analysis skills to make a fortune is casually on my to-do list. This blog makes regular use of a function getSymbols in the quantmod package. The power and simplicity

If you haven’t read yesterday’s post, I advise you to do so, because this is the fix of yesterday. Day #27: A lot of graphics in one place I found out how to use ggplot2 in knime. Say, for example, your code is this: library(ggplot2) myplot...

What is the effect on predicted and realized volatility of substituting risk fraction constraints for weight constraints? Previously This post depends on two previous blog posts: “Unproxying weight constraints” “Weight compared to risk fraction” The exact same sets of random portfolios are used in this post that were generated in the second of these. Payoff … Continue reading...

We left the last post at the point of determining the best ARMA model. Before continuing the discussion, however, I would like to make a few points that might seem a bit questionable or unclear: We model the daily returns instead of the prices. There are multiples reasons: this way financial series usually become stationary,

assignment in R Today my internship-promotor gave me the assignment to create this chart in R. This means: I get a lot of data and put a certain column on a barchart for each plate. On top of that data, you place 2 errorbars. At first I thought, piece ...

I love the idea of using R+LaTeX+Sweave for reproducible research. This is even easier now that R has a jazzy new IDE that supports Sweave syntax highlighting and automatic PDF generation. I know I'm going to take some flak for saying this, but let's ...

ComputerWorld's feature today, 22 free tools for data visualization and analysis, suggests open-source R as the third entry on the list: What it does: R is a general statistical analysis platform (the authors call it an "environment") that runs on the command line. Need to find means, medians, standard deviations, correlations? R can handle that and much more, including...

Matthew Yglesias shares this graph from the Economist: I hate this graph. OK, sure, I don't hate hate hate hate it: it's not a 3-d exploding pie chart or anything. It's not misleading, it's just extremely difficult to read. Basically,...

By popular demand, here's my R script for the time-use graphs:...