Publications by Theory meets practice...
Amazon’s Hanging Cable Problem (Golden Gate Edition)
Abstract: In this post we use R’s capabilities to solve nonlinear equation systems in order to answer an extension of the hanging cable problem to suspension bridges. We then use R and ggplot to overlay the solution to an image of the Golden Gate Bridge in order to bring together theory and practice. This work is licensed under a Creative Co...
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Judging Freehand Circle Drawing Competitions
Abstract: In 2007 Alexander Overwijk went viral with his ‘Perfect Circle’ video. The same year a World Freehand Circle Drawing Championship was organized, which he won. In this post we show how a mobile camera, R and the imager package can be used to develop an image analysis based method to judge future instances of the championship. This...
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Is the answer to everything Gaussian?
Abstract: As an applied statistician you get in touch with many challenging problems in need of a statistical solution. Often, your client/colleague already has a working solution and just wants to clarify a small statistical detail with you. Equally often, your intuition suggests you that the working solution is not statistically adequate, but h...
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Purr yourself into a math genius
Abstract: We use the purrr package to solve a popular math puzzle via a combinatorial functional programming approach. A small shiny app is provided to allow the user to solve their own variations of the puzzle. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. The markdown+Rknitr source code of t...
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A Shiny app for your perfect circle
Abstract: The perfect circle is a shiny app providing a user friendly interface to the algorithm described in the previous blog post Judging Freehand Circle Drawing Competitions. The app allows one to score freehand circles directly from the mobile by uploading photos of them them to a shiny server. An R package “perfectcircle” contains the s...
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Speedmining the Cubing Community with dbplyr
Abstract: We use the RMariaDB and dbplyr packages to analyze the results database of the World Cubing Association. In particular we are interested in finding unofficial world records of fastest 3x3x3 solves, countries with large proportion of female cubers as well as acceptable solving times before entering a WCA competition. This work is lice...
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Scraping the Sugarcoat
Abstract: Web-scraped data are used to put a Rubik’s cube competition result into perspective. The sugarcoating consists of altering the sampling frame of the comparison to the more relevant population of senior first time cubers. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. The markdown+Rk...
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Flatten the COVID-19 curve
Abstract: We discuss why the message of flattening the COVID-19 curve is right, but why some of the visualizations used to show the effect are wrong: Reducing the basic reproduction number does not just stretch the outbreak, it also reduces the final size of the outbreak. This work is licensed under a Creative Commons Attribution-ShareAlike 4....
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Effective reproduction number estimation
Abstract: We discuss the estimation with R of the time-varying effective reproduction number during an infectious disease outbreak such as the COVID-19 outbreak. Using a single simulated outbreak we compare the performance of three different estimation methods. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 Internati...
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Superspreading and the Gini Coefficient
Abstract: We look at superspreading in infectious disease transmission from a statistical point of view. We characterise heterogeneity in the offspring distribution by the Gini coefficient instead of the usual dispersion parameter of the negative binomial distribution. This allows us to consider more flexible offspring distributions. This work...
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