Publications by Markus Gesmann
Predicting events, when they haven’t happened yet
Suppose you have to predict the probabilities of events which haven’t happened yet. How do you do this?Here is an example from the 1950s when Longley-Cook, an actuary at an insurance company, was asked to price the risk for a mid-air collision of two planes, an event which as far as he knew hadn’t happened before. The civilian air...
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Hello Stan!
In my previous post I discussed how Longley-Cook, an actuary at an insurance company in the 1950’s, used Bayesian reasoning to estimate the probability for a mid-air collision of two planes.Here I will use the same model to get started with Stan/RStan, a probabilistic programming language for Bayesian inference. Last week my prior w...
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Posterior predictive output with Stan
I continue my Stan experiments with another insurance example. Here I am particular interested in the posterior predictive distribution from only three data points. Or, to put it differently I have a customer of three years and I’d like to predict the expected claims cost for the next year to set or adjust the premium.The example is...
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Communicating Risk at the Bay Area R User Group
I will be speaking at the Bay Area User Group meeting tonight about Communicating Risk. Anthony Goldbloom from Kaggle and Karim Chine from ElasticR will be there as well. The meeting will be at Microsoft in Mountain View.Later this week I will give a similar presentation at the R in Finance conference in Chicago. Please get in touch i...
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Back from R/Finance in Chicago
I had a great time at the R/Finance conference in Chicago last Friday/Saturday. Some brief takeaways for me were:From Emanuel Derman’s talk: It is is important to distinguish between theories and models. Theories live in an abstract world and for a given set of axioms they can be proven right. However, models live in the real world,...
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Using system and web fonts in R plots
The forthcoming R Journal has an interesting article on the showtext package by Yixuan Qiu. The package allows me to use system and web fonts directly in R plots, reminding me a little of the approach taken by XeLaTeX. But “unlike other methods to embed fonts into graphics, showtext converts text into raster images or polygons, and ...
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How to place titles in lattice plots
I like the Economist theme in the latticeExtra package. It produces nice looking charts that mimic the design of the weekly newspaper, such as in this example:For some time I wondered how I could put the title of my lattice plots into the top left corner as well (by default titles are centred). Reviewing the code of the theEconomist.t...
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Next Kölner R User Meeting: Friday, 26 June 2015
The next Cologne R user group meeting is scheduled for this Friday, 6 June 2015 and we have an exciting agenda with two talks followed by networking drinks. Data Science at the Commandline (Kirill Pomogajko)An Introduction to RStan and the Stan Modelling Language (Paul Viefers)Please note: Our venue changed! We have outgrown the seminar room at t...
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Notes from the Kölner R meeting, 26 June 2015
Last Friday the Cologne R user group came together for the 14th time, and for the first time we met at Startplatz, a start-up incubator venue. The venue was excellent, not only did they provide us with a much larger room, but also with the whole infrastructure, including table-football and drinks. Many thanks to Kirill for organising ...
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Adding mathematical notations to R plots
I have to admit that I find the plotmath expressions in R a little fiddly to annotate plots with mathematical notation. Apparently I am not the only one, but Stefano Meschiari did actually something about it. A few days ago his package latex2exp appeared on CRAN. The package provides the wonderful function latex2exp that translates La...
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